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1
Savard, N., G. Fubiani, R. Baartman, and M. Dehnel. "Implicit particle-in-cell development for ion source plasmas." Journal of Physics: Conference Series 2743, no. 1 (May 1, 2024): 012003. http://dx.doi.org/10.1088/1742-6596/2743/1/012003.
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Abstract Particle-in-Cell (PIC) codes used to study plasma dynamics within ion sources typically use an explicit scheme. These methods can be slow when simulating regions of high electron density in ion sources, which require resolving the Debye length in space and the plasma frequency in time. Recent developments on fully-implicit PIC models in curvilinear geometries have shown that these spatial/time scales can be significantly decreased/increased respectively, allowing for notable speed-ups in simulation time, and thus making it a potential tool for studying the physics of ion sources. For this purpose, a charge and energy conserving implicit PIC code has been developed in 1D to determine its potential for simulating bounded plasmas. In this paper, we use this model to simulate a 1D benchmark of a bounded plasma with fixed plasma density and electron/ion temperatures. The results are shown to compare well to the benchmark and to the results using an explicit PIC code. It is shown that the total amount of macro-particles used in the simulation is a better figure of merit for accurate results than the standard particles per cell used in literature. Significant speed-ups in computation time can be achieved for high plasma densities if the accuracy requirements are relaxed. In this case, we demonstrate the ability of the implicit PIC code to speed-up simulation time by nearly a factor of 12 compared to explicit PIC.
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Cao, Zhe, and Ming Li. "INCLUSION OF CONTACT FRICTION FOR PARTICLE-BASED SIMULATION OF SEDIMENT TRANSPORT OVER MOBILE BED." Coastal Engineering Proceedings, no. 37 (September 1, 2023): 34. http://dx.doi.org/10.9753/icce.v37.sediment.34.
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The particle based approach, including the particle resolving method, such as CFD-DEM, e.g. Drake and Calantoni (2001), Schmeeckle (2014), and the Particle-In-Cell (PIC) method, e.g. Patankar and Joseph (2001); Finn, M. Li, and Apte (2016); Y. Li et al. (2014), has become important tool for simulation of sediment transport in recent years. The latter is advantageous in the required computing resources when large amount of particles are involved and hence is more suitable for simulation of sediment transport over mobile bed. However, unlike that in CFD-DEM, special treatment is needed in the PIC method in order to prevent overlap and over-packing of sediment particles in a computational cell. Most models so far ignore the contact friction force between particles that hinders relative movement but often is essential to maintain particles in static position, especially in the seabed where the contact forces between particles are the largest. An new friction force is proposed to simulate the particle interactions, similar to the collision used in previous studies, so that the kinetic energy driving particles motion can be effectively dissipated and over-packing can be minimised under either static or dynamic stages of the particle motion.
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Che, Ju, Pei Yun Yi, Yu Jun Deng, Lin Fa Peng, and Xin Min Lai. "The Effect of Electrode Voltage on Acetylene Plasma Deposition Particles during the Preparation of PECVD Carbon Film Based on PIC-MCC Simulation." Materials Science Forum 1102 (October 24, 2023): 97–103. http://dx.doi.org/10.4028/p-ayra6n.
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At present, the preparation of conductive and corrosion-resistant carbon coatings by plasma-assisted chemical vapor deposition (PECVD) has received extensive research. In this paper, the acetylene plasma model was established by using the Particle in Cell/Monte Carlo method (PIC/MCC) to study the influence of different electrode voltages on the composition and particle energy of deposited particles, and explore the corresponding relationship between acetylene gas and deposited particles. The results show that increasing the electrode voltage can reduce the density of acetylene particles in the plasma, increase the ionization rate of acetylene, and reduce the particle density of C2 and CH groups. The energies of C2H2 and CH particles increase with the increase of voltage, while the energies of C2 and H particles are basically stable and not affected by the voltage. Keywords: PECVD, PIC/MCC, carbon film, electrode voltage, acetylene plasma, deposition particles.
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Konior, Wojciech. "Particle-In-Cell Electrostatic Numerical Algorithm." Transactions on Aerospace Research 2017, no. 3 (September 1, 2017): 24–45. http://dx.doi.org/10.2478/tar-2017-0020.
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Abstract Existing global models of interaction between the solar wind (SW) and the local interstellar medium (LISM) describe the heliosphere that arises as a result of this interaction. There is a strong motivation to develop a kinetic model using the Particle-in-Cell (PIC) method to describe phenomena which appear in the heliosphere. This is however a long term scientific goal. This paper describes an electrostatic Particle-in-Cell numerical model developed in the Institute of Aviation in Warsaw, which includes mechanical and charge exchange collisions between particles in the probabilistic manner using Direct Simulation Monte Carlo method. This is the first step into developing simulations of the heliosphere incorporating kinetic effects in collisionless plasmas. In this paper we focus only on presenting the work, which have been done on the numerical PIC algorithm.
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COULAUD, O., E. SONNENDRÜCKER, E. DILLON, P. BERTRAND, and A. GHIZZO. "Parallelization of semi-Lagrangian Vlasov codes." Journal of Plasma Physics 61, no. 3 (April 1999): 435–48. http://dx.doi.org/10.1017/s0022377899007527.
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We describe the parallel implementation of semi-Lagrangian Vlasov solvers, which are an alternative to particle-in-cell (PIC) simulations for the numerical investigation of the behaviour of charged particles in their self-consistent electromagnetic fields. The semi-Lagrangian method, which couples the Lagrangian and Eulerian points of view, is particularly interesting on parallel computers, since the solution is computed on grid points, the number of which remains constant in time on each processor, unlike the number of particles in PIC simulations, and thus greatly simplifies the parallelization process.
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Trotta, D., D. Burgess, G. Prete, S. Perri, and G. Zimbardo. "Particle transport in hybrid PIC shock simulations: A comparison of diagnostics." Monthly Notices of the Royal Astronomical Society 491, no. 1 (October 12, 2019): 580–95. http://dx.doi.org/10.1093/mnras/stz2760.
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ABSTRACT Recent in situ and remote observations suggest that the transport regime associated with shock-accelerated particles may be anomalous i.e. the mean square displacement (MSD) of such particles scales non-linearly with time. We use self-consistent hybrid particle-in-cell plasma simulations to simulate a quasi-parallel shock with parameters compatible with heliospheric shocks, and gain insights about the particle transport in such a system. For suprathermal particles interacting with the shock we compute the MSD separately in the upstream and downstream regions. Tracking suprathermal particles for sufficiently long times up and/or downstream of the shock poses problems in particle plasma simulations, such as statistically poor particle ensembles and trajectory fragments of variable length in time. Therefore, we introduce the use of time-averaged mean square displacement (TAMSD), which is based on single-particle trajectories, as an additional technique to address the transport regime for the upstream and the downstream regions. MSD and TAMSD are in agreement for the upstream energetic particle population, and both give a strong indication of superdiffusive transport, consistent with interplanetary shock observations. MSD and TAMSD are also in reasonable agreement downstream, where indications of anomalous transport are also found. TAMSD shows evidence of heterogeneity in the diffusion properties of the downstream particle population, ranging from subdiffusive behaviour of particles trapped in the strong magnetic field fluctuations generated at the shock to superdiffusive behaviour of particles transmitted and moving away from the shock.
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van Marle, Allard Jan, Artem Bohdan, Paul J. Morris, Martin Pohl, and Alexandre Marcowith. "Diffusive Shock Acceleration at Oblique High Mach Number Shocks." Astrophysical Journal 929, no. 1 (April 1, 2022): 7. http://dx.doi.org/10.3847/1538-4357/ac5962.
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Abstract The current paradigm of cosmic-ray (CR) origin states that the greater part of galactic CRs is produced by supernova remnants. The interaction of supernova ejecta with the interstellar medium after a supernova's explosions results in shocks responsible for CR acceleration via diffusive shock acceleration (DSA). We use particle-in-cell (PIC) simulations and a combined PIC-magnetohydrodynamic (PIC-MHD) technique to investigate whether DSA can occur in oblique high Mach number shocks. Using the PIC method, we follow the formation of the shock and determine the fraction of the particles that gets involved in DSA. With this result, we use PIC-MHD simulations to model the large-scale structure of the plasma and the magnetic field surrounding the shock and find out whether or not the reflected particles can generate upstream turbulence and trigger DSA. We find that the feasibility of this process in oblique shocks depends strongly on the Alfvénic Mach number, and the DSA process is more likely to be triggered at high Mach number shocks.
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Tomita, Sara, Yutaka Ohira, Shigeo S. Kimura, Kengo Tomida, and Kenji Toma. "Interaction of a Relativistic Magnetized Collisionless Shock with a Dense Clump." Astrophysical Journal Letters 936, no. 1 (August 29, 2022): L9. http://dx.doi.org/10.3847/2041-8213/ac88be.
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Abstract The interactions between a relativistic magnetized collisionless shock and dense clumps have been expected to play a crucial role in magnetic field amplification and cosmic-ray acceleration. We investigate this process using two-dimensional Particle-In-Cell (PIC) simulations, for the first time, where the clump size is much larger than the gyroradius of the downstream particles. We also perform relativistic magnetohydrodynamic (MHD) simulations for the same condition, to see the kinetic effects. We find that particles escape from the shocked clump along magnetic field lines in the PIC simulations, so that the vorticity is lower than that in the MHD simulations. Moreover, in both the PIC and MHD simulations, the shocked clump quickly decelerates because of relativistic effects. Owing to the escape and the deceleration, the shocked clump cannot amplify the downstream magnetic field in relativistic collisionless shocks. This large-scale PIC simulation opens a new window to understanding large-scale behaviors in collisionless plasma systems.
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Takahashi, Hiroyuki, Eiji Asano, and Ryoji Matsumoto. "Particle acceleration by relativistic expansion of magnetic arcades." Proceedings of the International Astronomical Union 2, no. 14 (August 2006): 102. http://dx.doi.org/10.1017/s1743921307010022.
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AbstractWe carried out relativistic force free simulations and Particle In Cell (PIC) simulations of twist injection into the magnetic arcades emerging on the surface of a magnetar. As the magnetic energy is accumulated in the arcades, they expand self-similarly. In the arcades, a current sheet is formed and magnetic reconnection takes place. We also carried out 2-dimensional PIC simulations for the study of particle acceleration through magnetic reconnection. As a result, the energy spectrum of particles can be fitted by a power-law.
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Gomez, Sara, Jaime Humberto Hoyos, and Juan Alejandro Valdivia. "Particle-in-cell method for plasmas in the one-dimensional electrostatic limit." American Journal of Physics 91, no. 3 (March 2023): 225–34. http://dx.doi.org/10.1119/5.0135515.
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We discuss the particle-in-cell (PIC) method, which is one of the most widely used approaches for the kinetic description of plasmas. The positions and velocities of the charged particles take continuous values in phase space, and spatial macroscopic quantities, such as the charge density and self-generated electric fields, are calculated at discrete spatial points of a grid. We discuss the computer implementation of the PIC method for one-dimensional plasmas in the electrostatic regime and discuss a desktop application (PlasmAPP), which includes the implementation of different numerical and interpolation methods and diagnostics in a graphical user interface. To illustrate its functionality, the electron-electron two-stream instability is discussed. Readers can use PlasmAPP to explore advanced numerical methods and simulate different phenomena of interest.
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Marle, Allard Jan van, Artem Bohdan, Anabella Araudo, Fabien Casse, and Alexandre Marcowith. "Diffusive shock acceleration in relativistic, oblique shocks." Journal of Physics: Conference Series 2742, no. 1 (April 1, 2024): 012008. http://dx.doi.org/10.1088/1742-6596/2742/1/012008.
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Abstract Cosmic rays are charged particles that are accelerated to relativistic speeds by astrophysical shocks. Numerical models have been successful in confirming the acceleration process for (quasi-)parallel shocks, which have the magnetic field aligned with the direction of the shock motion. However, the process is less clear when it comes to (quasi-)perpendicular shocks, where the field makes a large angle with the shock-normal. For such shocks, the angle between the magnetic field and flow ensures that only highly energetic particles can travel upstream at all, reducing the upstream current. This process is further inhibited for relativistic shocks, since the shock can become superluminal when the required particle velocity exceeds the speed of light, effectively inhibiting any upstream particle flow. In order to determine whether such shocks can accelerate particles, we use the particle-in-cell (PIC) method to determine what fraction of particles gets reflected initially at the shock. We then use this as input for a new simulation that combines the PIC method with grid-based magnetohydrodynamics to follow the acceleration (if any) of the particles over a larger time-period in a two-dimensional grid. We find that quasi-perpendicular, relativistic shocks are capable of accelerating particles through the DSA process, provided that the shock has a sufficiently high Alfvénic Mach number.
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Chang, L., G. Bourianoff, B. Cole, and S. Machida. "A Parallel Implementation of Particle Tracking with Space Charge Effects on an Intel iPSC/860." Scientific Programming 2, no. 3 (1993): 37–47. http://dx.doi.org/10.1155/1993/397679.
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Particle-tracking simulation is one of the scientific applications that is well suited to parallel computations. At the Superconducting Super Collider, it has been theoretically and empirically demonstrated that particle tracking on a designed lattice can achieve very high parallel efficiency on a MIMD Intel iPSC/860 machine. The key to such success is the realization that the particles can be tracked independently without considering their interaction. The perfectly parallel nature of particle tracking is broken if the interaction effects between particles are included. The space charge introduces an electromagnetic force that will affect the motion of tracked particles in three-dimensional (3-D) space. For accurate modeling of the beam dynamics with space charge effects, one needs to solve 3-D Maxwell field equations, usually by a particle-in-cell (PIC) algorithm. This will require each particle to communicate with its neighbor grids to compute the momentum changes at each time step. It is expected that the 3-D PIC method will degrade parallel efficiency of particle-tracking implementation on any parallel computer. In this paper, we describe an efficient scheme for implementing particle tracking with space charge effects on an INTEL iPSC/860 machine. Experimental results show that a parallel efficiency of 75% can be obtained.
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Lu, Yingchao, Fan Guo, Patrick Kilian, Hui Li, Chengkun Huang, and Edison Liang. "Studying particle acceleration from driven magnetic reconnection at the termination shock of a relativistic striped wind using particle-in-cell simulations." EPJ Web of Conferences 235 (2020): 07003. http://dx.doi.org/10.1051/epjconf/202023507003.
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A rotating pulsar creates a surrounding pulsar wind nebula (PWN) by steadily releasing an energetic wind into the interior of the expanding shockwave of supernova remnant or interstellar medium. At the termination shock of a PWN, the Poynting-flux- dominated relativistic striped wind is compressed. Magnetic reconnection is driven by the compression and converts magnetic energy into particle kinetic energy and accelerating particles to high energies. We carrying out particle-in-cell (PIC) simulations to study the shock structure as well as the energy conversion and particle acceleration mechanism. By analyzing particle trajectories, we find that many particles are accelerated by Fermi-type mechanism. The maximum energy for electrons and positrons can reach hundreds of TeV.
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Gallo, Giuseppe, Adriano Isoldi, Dario Del Gatto, Raffaele Savino, Amedeo Capozzoli, Claudio Curcio, and Angelo Liseno. "Numerical Aspects of Particle-in-Cell Simulations for Plasma-Motion Modeling of Electric Thrusters." Aerospace 8, no. 5 (May 15, 2021): 138. http://dx.doi.org/10.3390/aerospace8050138.
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The present work is focused on a detailed description of an in-house, particle-in-cell code developed by the authors, whose main aim is to perform highly accurate plasma simulations on an off-the-shelf computing platform in a relatively short computational time, despite the large number of macro-particles employed in the computation. A smart strategy to set up the code is proposed, and in particular, the parallel calculation in GPU is explored as a possible solution for the reduction in computing time. An application on a Hall-effect thruster is shown to validate the PIC numerical model and to highlight the strengths of introducing highly accurate schemes for the electric field interpolation and the macroparticle trajectory integration in the time. A further application on a helicon double-layer thruster is presented, in which the particle-in-cell (PIC) code is used as a fast tool to analyze the performance of these specific electric motors.
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Wang, Yao-Ting, Jian Chen, He-Ping Li, Dong-Jun Jiang, and Ming-Sheng Zhou. "Analysis and particle-in-cell simulation on the similarity relation during an ion extraction process." Journal of Physics: Conference Series 2147, no. 1 (January 1, 2022): 012013. http://dx.doi.org/10.1088/1742-6596/2147/1/012013.
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Abstract Ion extraction time is one of the key parameters for an ion extraction process. Particle-in-cell (PIC) simulation can provide a detailed description on the charged-particle behaviours during the ion extraction process in a decaying plasma. However, the PIC modelling is a very time-consuming task with very small space step (~ Debye length) and time step (~ inverse of plasma frequency), as well as a massive number of macro-particles, especially for the cases in multi-dimensions and large geometrical sizes. In this paper, based on the sheath expansion and ion-acoustic rarefaction wave propagation model, a similarity relation of ion extraction time with different geometrical sizes of the ion extraction regions is established. The theoretical analysis shows that, by changing the magnitude of the externally applied voltage to keep the ion extraction flux equal, the ion extraction time is proportional to the geometrical size ratio. Then, the PIC simulations on the ion extraction process are conducted, which show that there exists a good consistency with the theoretical analysis and previous experimental data. This research is helpful for promoting numerical simulations facing actual ion extraction processes with large geometrical sizes and provides theoretical guidance for improving the ion extraction efficiencies in applications.
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Yang, Fuxiang, Jie Li, Chuanfu Xu, Dali Li, Haozhong Qiu, and Ao Xu. "MPI Parallelization of Numerical Simulations for Pulsed Vacuum Arc Plasma Plumes Based on a Hybrid DSMC/PIC Algorithm." Aerospace 9, no. 10 (September 23, 2022): 538. http://dx.doi.org/10.3390/aerospace9100538.
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The transport characteristics of the unsteady flow field in rarefied plasma plumes is crucial for a pulsed vacuum arc in which the particle distribution varies from 1016 to 1022 m−3. The direct simulation Monte Carlo (DSMC) method and particle-in-cell (PIC) method are generally combined to study this kind of flow field. The DSMC method simulates the motion of neutral particles, while the PIC method simulates the motion of charged ions. A hybrid DSMC/PIC algorithm is investigated here to determine the unsteady axisymmetric flow characteristics of vacuum arc plasma plume expansion. Numerical simulations are found to be consistent with the experiments performed in the plasma mass and energy analyzer (EQP). The electric field is solved by Poisson’s equation, which is usually computationally expensive. The compressed sparse row (CSR) format is used to store the huge diluted matrix and PETSc library to solve Poisson’s equation through parallel calculations. Double weight factors and two timesteps under two grid sets are investigated using the hybrid DSMC/PIC algorithm. The fine PIC grid is nested in the coarse DSMC grid. Therefore, METIS is used to divide the much smaller coarse DSMC grid when dynamic load imbalances arise. Two parameters are employed to evaluate and distribute the computational load of each process. Due to the self-adaption of the dynamic-load-balancing parameters, millions of grids and more than 150 million particles are employed to predict the transport characteristics of the rarefied plasma plume. Atomic Ti and Ti2+ are injected into the small cylinders. The comparative analysis shows that the diffusion rate of Ti2+ is faster than that of atomic Ti under the electric field, especially in the z-direction. The fully diffuse reflection wall model is adopted, showing that neutral particles accumulate on the wall, while charged ions do not—due to their self-consistent electric field. The maximum acceleration ratio is about 17.94.
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Hasegawa, Hiroki, and Seiji Ishiguro. "Microscopic Effect on Filamentary Coherent Structure Dynamics in Boundary Layer Plasmas." Plasma 1, no. 1 (March 22, 2018): 61–67. http://dx.doi.org/10.3390/plasma1010006.
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This study has demonstrated kinetic behaviors on the plasma filament propagation with the three-dimensional (3D) Particle-in-Cell (PIC) simulation. When the ion-to-electron temperature ratio T i / T e is higher, the poloidal symmetry breaking in the filament propagation occurs. The poloidal symmetry breaking is thought to be induced by the unbalanced potential structure that arises from the effect of the gyro motion of plasma particles.
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Li, Zhang, Wu, Cheng, and Du. "Particle Simulation Model for Self-Field Magnetoplasmadynamic Thruster." Energies 12, no. 8 (April 25, 2019): 1579. http://dx.doi.org/10.3390/en12081579.
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In order to clarify the discharge principle of the self-field magnetoplasmadynamic thruster (MPDT), a two-dimensional axisymmetric particle-in-cell/Monte Carlo collision (PIC/MCC) model is proposed. The spatial distribution and the collision characteristics of discharge plasma were calculated using this model. In addition, the influence of the operation parameters on the plasma was analyzed including the voltage and mass flow rate. The effectiveness of the model was verified by comparison to the experimentally induced magnetic field. It was found that the electrons were mainly accelerated by the electric field in the cathode sheath and the electric field shielding effect of plasma was obvious in the bulk plasma region. Due to the pinch effect, the charged particles were constrained near the cathode. The results of the present work implied that the PIC/MCC model provides an approach to investigate the plasma distribution and a kinetic description of particles for the discharge of the self-field MPDT.
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J, Ananthanarasimhan, Anand M.S., and Lakshminarayana R. "Simulation of Velocity Evolution of a Cold Collision-less Non-Magnetised Plasma by Particle-in-Cell Method." Frontiers in Advanced Materials Research 2, no. 2 (January 15, 2021): 18–25. http://dx.doi.org/10.34256/famr2023.
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This work presents simple numerical simulation algorithm to analyse the velocity evolution of high density non-magnetized glow discharge (cold) collision-less plasma using Particle-in-Cell (PIC) method. In the place of millions of physical electrons and background ions, fewer particles called super particles are used for simulation to capture the plasma properties such as particle velocity, particle energy and electrical field of the plasma system. The plasma system which is of interest in this work is weakly coupled plasma having quasi-neutrality nature. Simulation results showed symmetric velocity distribution about zero with slight left skewness, indicating static system. The order of directional velocity of individual particle seems to agree with the input electron temperature of the considered plasma system. The particle and field energy evolution were observed having fluctuations about zero which indicates that the system is equilibrating. This work marks the preliminary work to study the transport of plasma species in plasma column of gliding arc discharge.
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Petrov, George M., and Jack Davis. "Parallelization of an Implicit Algorithm for Multi-Dimensional Particle-in-Cell Simulations." Communications in Computational Physics 16, no. 3 (September 2014): 599–611. http://dx.doi.org/10.4208/cicp.070813.280214a.
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AbstractThe implicit 2D3V particle-in-cell (PIC) code developed to study the interaction of ultrashort pulse lasers with matter [G. M. Petrov and J. Davis, Computer Phys. Comm. 179, 868 (2008); Phys. Plasmas 18, 073102 (2011)] has been parallelized using MPI (Message Passing Interface). The parallelization strategy is optimized for a small number of computer cores, up to about 64. Details on the algorithm implementation are given with emphasis on code optimization by overlapping computations with communications. Performance evaluation for 1D domain decomposition has been made on a small Linux cluster with 64 computer cores for two typical regimes of PIC operation: “particle dominated”, for which the bulk of the computation time is spent on pushing particles, and “field dominated”, for which computing the fields is prevalent. For a small number of computer cores, less than 32, the MPI implementation offers a significant numerical speed-up. In the “particle dominated” regime it is close to the maximum theoretical one, while in the “field dominated” regime it is about 75-80 % of the maximum speed-up. For a number of cores exceeding 32, performance degradation takes place as a result of the adopted 1D domain decomposition. The code parallelization will allow future implementation of atomic physics and extension to three dimensions.
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Xia, Q., and V. Zharkova. "Particle acceleration in coalescent and squashed magnetic islands." Astronomy & Astrophysics 635 (March 2020): A116. http://dx.doi.org/10.1051/0004-6361/201936420.
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Aims. Particles are known to have efficient acceleration in reconnecting current sheets with multiple magnetic islands that are formed during a reconnection process. Using the test-particle approach, the recent investigation of particle dynamics in 3D magnetic islands, or current sheets with multiple X- and O-null points revealed that the particle energy gains are higher in squashed magnetic islands than in coalescent ones. However, this approach did not factor in the ambient plasma feedback to the presence of accelerated particles, which affects their distributions within the acceleration region. Methods. In the current paper, we use the particle-in-cell (PIC) approach to investigate further particle acceleration in 3D Harris-type reconnecting current sheets with coalescent (merging) and squashed (contracting) magnetic islands with different magnetic field topologies, ambient densities ranging between 108 − 1012 m−3, proton-to-electron mass ratios, and island aspect ratios. Results. In current sheets with single or multiple X-nullpoints, accelerated particles of opposite charges are separated and ejected into the opposite semiplanes from the current sheet midplane, generating a strong polarisation electric field across a current sheet. Particles of the same charge form two populations: transit and bounced particles, each with very different energy and asymmetric pitch-angle distributions, which can be distinguished from observations. In some cases, the difference in energy gains by transit and bounced particles leads to turbulence generated by Buneman instability. In magnetic island topology, the different reconnection electric fields in squashed and coalescent islands impose different particle drift motions. This makes particle acceleration more efficient in squashed magnetic islands than in coalescent ones. The spectral indices of electron energy spectra are ∼ − 4.2 for coalescent and ∼ − 4.0 for squashed islands, which are lower than reported from the test-particle approach. The particles accelerated in magnetic islands are found trapped in the midplane of squashed islands, and shifted as clouds towards the X-nullpoints in coalescent ones. Conclusions. In reconnecting current sheets with multiple X- and O-nullpoints, particles are found accelerated on a much shorter spatial scale and gaining higher energies than near a single X-nullpoint. The distinct density and pitch-angle distributions of particles with high and low energy detected with the PIC approach can help to distinguish the observational features of accelerated particles.
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Kovalev, D. V., A. P. Smirnov, and Y. S. Dimant. "Modeling of the Farley-Buneman instability in the E-region ionosphere: a new hybrid approach." Annales Geophysicae 26, no. 9 (September 23, 2008): 2853–70. http://dx.doi.org/10.5194/angeo-26-2853-2008.
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Abstract. A novel approach to nonlinear simulations of the Farley-Buneman (FB) instability in the E-region ionosphere is developed. The mathematical model includes a fluid description of electrons and a simplified kinetic description of ions based on a kinetic equation with the Bhatnagar-Gross-Crook (BGK) collision term. This hybrid model takes into account all major factors crucial for development and nonlinear stabilization of the instability (collisional drag forces, ion inertia and Landau damping, dominant electron nonlinearity, etc.). At the same time, these simulations are free of noises caused by the finite number of particles and may require less computer resources than particle-in-cell (PIC) or hybrid – semi-fluid semi-PIC – simulations. First results of 2-D simulations are presented which agree reasonably well with those of previous 2-D PIC simulations. One of the potentially useful applications of the novel computational approach is modeling of the FB instability not far from its threshold.
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Zhang, Ling-Yu, Xiao-Ying Zhao, Xin Qi, Guo-Qing Xiao, Wen-Shan Duan, and Lei Yang. "Wakefield and stopping power of a hydrogen ion beam pulse with low drift velocity in hydrogen plasmas." Laser and Particle Beams 33, no. 2 (March 23, 2015): 215–20. http://dx.doi.org/10.1017/s0263034615000270.
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AbstractA two-dimensional particle-in-cell (PIC) simulation is carried out to study the wakefield and stopping power for a hydrogen ion beam pulse with low drift velocity propagation in hydrogen plasmas. The plasma is assumed to be collisionless, uniform, non-magnetized, and in a steady state. Both the pulse ions and plasma particles are treated by the PIC method. The effects of the beam density on the wakefield and stopping power are then obtained and discussed. It is found that as the beam densities increase, the oscillation wakefield induced by the beam become stronger. Besides, the first oscillation wakefield behind the bunch is particularly stronger than others. Moreover, it is found that the stationary stopping power increases linearly with the increase of the beam density in the linear/semilinear region.
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MELZANI, MICKAËL, ROLF WALDER, DORIS FOLINI, and CHRISTOPHE WINISDOERFFER. "DIFFERENCES BETWEEN REAL AND PARTICLE-IN-CELL PLASMAS: EFFECTS OF COARSE-GRAINING." International Journal of Modern Physics: Conference Series 28 (January 2014): 1460194. http://dx.doi.org/10.1142/s201019451460194x.
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The PIC model relies on two building blocks. The first stems from the capability of computers to handle only up to ~ 1010 particles, while real plasmas contain from 104 to 1020 particles per Debye sphere: a coarse-graining step must be used, whereby of the order of p ~ 1010 real particles are represented by a single computer superparticle. The second is field storage on a grid with its subsequent finite superparticle size. We introduce the notion of coarse-graining dependent quantities, i.e. physical quantities depending on the number p. They all derive from the plasma parameter Λ, which we show to be proportional to 1/p. We explore three examples: the rapid collision- and fluctuation-induced thermalization of plasmas with different temperatures, that scale with the number of superparticles per grid cell and are a factor p ~ 1010 faster than in real plasmas; the high level of electrostatic fluctuations in a thermal plasma, with corrections due to the finite superparticle sizes; and the blurring of the linear spectrum of the filamentation instability, where the fastest growing modes do not dominate the total energy because of a high level of fluctuations. We stress that the enhanced collisions and correlations of PIC plasmas must be kept negligible toward kinetic physics.
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Bacchini, Fabio. "RelSIM: A Relativistic Semi-implicit Method for Particle-in-cell Simulations." Astrophysical Journal Supplement Series 268, no. 2 (October 1, 2023): 60. http://dx.doi.org/10.3847/1538-4365/acefba.
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Abstract We present a novel Relativistic Semi-Implicit Method (RelSIM) for particle-in-cell (PIC) simulations of astrophysical plasmas, implemented in a code framework ready for production runs. While explicit PIC methods have gained widespread recognition in the astrophysical community as a reliable tool to simulate plasma phenomena, implicit methods have been seldom explored. This is partly due to the lack of a reliable relativistic implicit PIC formulation that is applicable to state-of-the-art simulations. We propose the RelSIM to fill this gap: our new method is relatively simple, being free of nonlinear iterations and only requiring a global linear solve of the field equations. With a set of one- and two-dimensional tests, we demonstrate that the RelSIM produces more accurate results with much smaller numerical errors in the total energy than standard explicit PIC, in particular when characteristic plasma scales (skin depth and plasma frequency) are heavily underresolved on the numerical grid. By construction, the RelSIM also performs much better than the relativistic implicit-moment method, originally proposed for semi-implicit PIC simulations in the relativistic regime. Our results are promising to conduct large-scale (in terms of duration and domain size) PIC simulations of astrophysical plasmas, potentially reaching physical regimes inaccessible by standard explicit PIC codes.
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Kin, Koki, Shota Kisaka, Kenji Toma, Shigeo S. Kimura, and Amir Levinson. "One-dimensional General Relativistic Particle-in-cell Simulations of Stellar-mass Black Hole Magnetospheres: A Semianalytic Model of Gamma-Rays from Gaps." Astrophysical Journal 964, no. 1 (March 1, 2024): 78. http://dx.doi.org/10.3847/1538-4357/ad20cd.
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Abstract In the absence of a sufficient amount of plasma injection into the black hole (BH) magnetosphere, the force-free state of the magnetosphere cannot be maintained, leading to the emergence of strong, time-dependent, longitudinal electric fields (i.e., spark gaps). Recent studies of supermassive BH magnetospheres using analytical methods and particle-in-cell (PIC) simulations propose the possibility of efficient particle acceleration and consequent gamma-ray emission in the spark gap. In this work, we perform 1D general relativistic PIC simulations to examine the gamma-ray emission from stellar-mass BH magnetospheres. We find that intermittent spark gaps emerge and particles are efficiently accelerated in a similar manner to the supermassive BH case. We build a semianalytic model of the plasma dynamics and radiative processes, which reproduces the maximum electron energies and peak gamma-ray luminosities of the simulation results. Based on this model, we show that the gamma-ray signals from stellar-mass BHs wandering through the interstellar medium could be detected by gamma-ray telescopes such as the Fermi Large Area Telescope or the Cherenkov Telescope Array.
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Lei, Li, Xiaolin Jin, Jibo Li, Lixuan Li, and Bin Li. "Some aspects of the plasma potential in 3D simulation of ECRIS operation." Physics of Plasmas 29, no. 7 (July 2022): 073904. http://dx.doi.org/10.1063/5.0097141.
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A 3D particle-in-cell plus Monte Carlo collision (PIC/MCC) code is developed for the simulation of electron cyclotron resonance ion source (ECRIS). The self-consistent interaction between the plasma and the potential field is taken into account, as well as Coulomb collisions, stepwise ionization, and charge exchange collisions between particles. In addition, a precalculation module based on a single-particle approach is introduced to speed up simulations. The stable distributions of the high-energy electrons are obtained and then sent to the subsequent simulation of ECRIS operation as the well-confined warm and hot electrons. An implicit electrostatic PIC model in this simulation self-consistently describes the evolution of the ECR plasma. The results are obtained for the plasma potential in a steady state, including the global amplitude and distribution profiles. The potential distribution of the ECR plasma is characterized by magnetic fields. These results, together with those for the charge density, are analyzed and discussed from the perspective of plasma diffusion.
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Semenov, V., D. Korovinskiy, A. Divin, N. Erkaev, and H. Biernat. "Collisionless magnetic reconnection: analytical model and PIC simulation comparison." Annales Geophysicae 27, no. 3 (March 2, 2009): 905–11. http://dx.doi.org/10.5194/angeo-27-905-2009.
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Abstract. Magnetic reconnection is believed to be responsible for various explosive processes in the space plasma including magnetospheric substorms. The Hall effect is proved to play a key role in the reconnection process. An analytical model of steady-state magnetic reconnection in a collisionless incompressible plasma is developed using the electron Hall MHD approximation. It is shown that the initial complicated system of equations may split into a system of independent equations, and the solution of the problem is based on the Grad-Shafranov equation for the magnetic potential. The results of the analytical study are further compared with a two-dimensional particle-in-cell simulation of reconnection. It is shown that both methods demonstrate a close agreement in the electron current and the magnetic and electric field structures obtained. The spatial scales of the acceleration region in the simulation and the analytical study are of the same order. Such features like particles trajectories and the in-plane electric field structure appear essentially similar in both models.
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Siddhamshetty, Prashanth, Shaowen Mao, Kan Wu, and Joseph Sang-Il Kwon. "Multi-Size Proppant Pumping Schedule of Hydraulic Fracturing: Application to a MP-PIC Model of Unconventional Reservoir for Enhanced Gas Production." Processes 8, no. 5 (May 12, 2020): 570. http://dx.doi.org/10.3390/pr8050570.
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Slickwater hydraulic fracturing is becoming a prevalent approach to economically recovering shale hydrocarbon. It is very important to understand the proppant’s transport behavior during slickwater hydraulic fracturing treatment for effective creation of a desired propped fracture geometry. The currently available models are either oversimplified or have been performed at limited length scales to avoid high computational requirements. Another limitation is that the currently available hydraulic fracturing simulators are developed using only single-sized proppant particles. Motivated by this, in this work, a computationally efficient, three-dimensional, multiphase particle-in-cell (MP-PIC) model was employed to simulate the multi-size proppant transport in a field-scale geometry using the Eulerian–Lagrangian framework. Instead of tracking each particle, groups of particles (called parcels) are tracked, which allows one to simulate the proppant transport in field-scale geometries at an affordable computational cost. Then, we found from our sensitivity study that pumping schedules significantly affect propped fracture surface area and average fracture conductivity, thereby influencing shale gas production. Motivated by these results, we propose an optimization framework using the MP-PIC model to design the multi-size proppant pumping schedule that maximizes shale gas production from unconventional reservoirs for given fracturing resources.
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Kang, Sang Hun. "PIC-DSMC Simulation of a Hall Thruster Plume with Charge Exchange Effects Using pdFOAM." Aerospace 10, no. 1 (January 3, 2023): 44. http://dx.doi.org/10.3390/aerospace10010044.
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To develop technologies for the stable operation of electric propulsion systems, the effects of charge exchange (CEX) on the exhaust plume of a Hall thruster were studied using the particle-in-cell direct simulation Monte Carlo (PIC-DSMC) method. For the numerical analysis, an OpenFOAM-based code, pdFOAM, with a simple electron fluid model was employed. In an example problem using the D55 Hall thruster exhaust plume, the results showed good agreement with experimental measurements of the plasma potential. In the results, CEX effects enhanced Xe+ particle scattering near the thruster exit. However, due to the increase in the plasma potential with CEX effects, fewer Xe2+ particles were near the thruster exit with CEX effects than without CEX effects.
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Alhakamy, Nabil A., Giuseppe Caruso, Mohammed W. Al-Rabia, Shaimaa M. Badr-Eldin, Hibah M. Aldawsari, Hani Z. Asfour, Samah Alshehri, et al. "Piceatannol-Loaded Bilosome-Stabilized Zein Protein Exhibits Enhanced Cytostatic and Apoptotic Activities in Lung Cancer Cells." Pharmaceutics 13, no. 5 (April 29, 2021): 638. http://dx.doi.org/10.3390/pharmaceutics13050638.
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Piceatannol (PIC) is a naturally occurring polyphenolic stilbene, and it has pleiotropic pharmacological properties. Moreover, PIC has cytotoxic actions among various cancer cells. In this work, preparations of PIC-loaded bilosome–zein (PIC-BZ) were designed, formulated, and characterized, and the optimized PIC-BZ cytotoxic activities, measured as half maximal inhibitory concentration (IC50), against lung cancer cell line was investigated. Box–Behnken design was utilized in order to examine the effect of preparation factors on drug entrapment and particle size. PIC-BZ showed a spherical shape after optimization, and its particle size was determined as 157.45 ± 1.62 nm. Moreover, the efficiency of drug entrapment was found as 93.14 ± 2.15%. The cytotoxic activity evaluation revealed that the adjusted formulation, which is PIC-BZ formula, showed a substantially smaller IC50 versus A549 cells. Cell cycle analysis showed accumulation of cells in the G2-M phase. Moreover, it showed in the sub-G1 phase, a rise of cell fraction suggestion apoptotic improving activity. Increased early and late phases of apoptosis were demonstrated by staining of cells with annexin V. Furthermore, the cellular caspase-3 protein expression was significantly raised by PIC-BZ. In addition, the wound healing experiment confirmed the results. To conclude, compared to pure PIC, PIC-BZ demonstrated a higher cell death-inducing activity against A549 cells.
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Veitzer, Seth A., and Daniel Main. "Advances in Particle-In-Cell Modeling of Low-Temperature Plasma Ion Sources." Journal of Physics: Conference Series 2743, no. 1 (May 1, 2024): 012021. http://dx.doi.org/10.1088/1742-6596/2743/1/012021.
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Abstract Ion sources that use low-temperature plasma (LTP) discharges are used in a variety of applications, including ion implantation, mass spectrometry, and plasma processing. In recent years there has been a growing interest in using particle-in-cell (PIC) modeling to improve the performance and optimization of LTP-based ion sources. PIC modeling is a powerful tool for simulating the dynamics of plasmas because it accurately models the effects of self-consistent fields, charge deposition, plasma chemistry, magnetic confinement, and accurate sheath physics. However, PIC simulations can be computationally demanding, especially for 3D systems. We present new advances in PIC modeling of LTP ion sources. We focus on two key challenges: 1. Efficient and accurate modeling of plasma chemistry: Plasma chemistry is a complex process that can have a significant impact on the performance of LTP ion sources. We demonstrate using global models to reduce the computational cost of plasma chemistry simulations, and diagnostics for understanding the physics of those reactions. 2. Energy-conserving PIC models: PIC simulations typically require a fine spatial grid in order to resolve the Debye length. This can be computationally expensive, especially for 3D systems. We present a new energy-conserving PIC model implementation that allows us to perform simulations without resolving the Debye length. We validate these methods on two different types of LTP ion sources: a Bernas source and a Penning source. Our results show that these methods can significantly improve the efficiency and accuracy of PIC simulations of LTP-based ion sources.
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ABUDUREXITI, A., Y. MIKADO, and T. OKADA. "ENERGETIC PROTON ACCELERATION BY ULTRAINTENSE LASER PULSES IN INHOMOGENEOUS PLASMA TARGETS." International Journal of Modern Physics B 21, no. 03n04 (February 10, 2007): 642–46. http://dx.doi.org/10.1142/s021797920704246x.
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Particle-in-Cell (PIC) simulations of fast particles produced by a short laser pulse with duration of 40 fs and an intensity of 1020W/cm2 interacting with a foil target are performed. The experimental process is numerically simulated by considering a triangular concave target illuminated by an ultraintense laser. We have demonstrated increased acceleration and higher proton energies for triangular concave targets. We also determined the optimum target plasma conditions for maximum proton acceleration. The results indicated that a change in the plasma target shape directly affects the degree of contraction accelerated proton bunch.
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Hoshi, Kento, Hirotsugu Kojima, Takanobu Muranaka, and Hiroshi Yamakawa. "Thrust calculation of electric solar wind sail by particle-in-cell simulation." Annales Geophysicae 34, no. 9 (September 26, 2016): 845–55. http://dx.doi.org/10.5194/angeo-34-845-2016.
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Abstract. In this study, thrust characteristics of an electric solar wind sail were numerically evaluated using full three-dimensional particle-in-cell (PIC) simulation. The thrust obtained from the PIC simulation was lower than the thrust estimations obtained in previous studies. The PIC simulation indicated that ambient electrons strongly shield the electrostatic potential of the tether of the sail, and the strong shield effect causes a greater thrust reduction than has been obtained in previous studies. Additionally, previous expressions of the thrust estimation were modified by using the shielded potential structure derived from the present simulation results. The modified thrust estimation agreed very well with the thrust obtained from the PIC simulation.
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Medina-Torrejón, Tania E., Elisabete M. de Gouveia Dal Pino, and Grzegorz Kowal. "Particle Acceleration by Magnetic Reconnection in Relativistic Jets: The Transition from Small to Large Scales." Astrophysical Journal 952, no. 2 (July 27, 2023): 168. http://dx.doi.org/10.3847/1538-4357/acd699.
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Abstract Several MHD works, and, in particular, the recent one by Medina-Torrejón et al. based on three-dimensional MHD simulations of relativistic jets, have evidenced that particle acceleration by magnetic reconnection driven by the turbulence in the flow occurs from the resistive up to the large injection scale of the turbulence. Particles experience Fermi-type acceleration up to ultrahigh energies, predominantly of the parallel velocity component to the local magnetic field, in the reconnection layers in all scales due to the ideal electric fields of the background fluctuations (V × B, where V and B are the velocity and magnetic field of the fluctuations, respectively). In this work, we show MHD-particle-in-cell (MHD-PIC) simulations following the early stages of the particle acceleration in the relativistic jet, which confirm these previous results, demonstrating the strong potential of magnetic reconnection driven by turbulence to accelerate relativistic particles to extreme energies in magnetically dominated flows. Our results also show that the dynamical time variations of the background magnetic fields do not influence the acceleration of the particles in this process.
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Leboeuf, Jean-Noel G., Viktor K. Decyk, David E. Newman, and Raul Sanchez. "Implementation of 2D Domain Decomposition in the UCAN Gyrokinetic Particle-in-Cell Code and Resulting Performance of UCAN2." Communications in Computational Physics 19, no. 1 (January 2016): 205–25. http://dx.doi.org/10.4208/cicp.070115.030715a.
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AbstractThe massively parallel, nonlinear, three-dimensional (3D), toroidal, electrostatic, gyrokinetic, particle-in-cell (PIC), Cartesian geometry UCAN code, with particle ions and adiabatic electrons, has been successfully exercised to identify non-diffusive transport characteristics in present day tokamak discharges. The limitation in applying UCAN to larger scale discharges is the 1D domain decomposition in the toroidal (or z-) direction for massively parallel implementation using MPI which has restricted the calculations to a few hundred ion Larmor radii or gyroradii per plasma minor radius. To exceed these sizes, we have implemented 2D domain decomposition in UCAN with the addition of the y-direction to the processor mix. This has been facilitated by use of relevant components in the P2LIB library of field and particle management routines developed for UCLA's UPIC Framework of conventional PIC codes. The gyro-averaging specific to gyrokinetic codes is simplified by the use of replicated arrays for efficient charge accumulation and force deposition. The 2D domain-decomposed UCAN2 code reproduces the original 1D domain nonlinear results within round-off. Benchmarks of UCAN2 on the Cray XC30 Edison at NERSC demonstrate ideal scaling when problem size is increased along with processor number up to the largest power of 2 available, namely 131,072 processors. These particle weak scaling benchmarks also indicate that the 1 nanosecond per particle per time step and 1 TFlops barriers are easily broken by UCAN2 with 1 billion particles or more and 2000 or more processors.
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Geiser, Jürgen, and Sven Blankenburg. "Plasma and BIAS Modeling: Self-Consistent Electrostatic Particle-in-Cell with Low-Density Argon Plasma for TiC." Modelling and Simulation in Engineering 2011 (2011): 1–13. http://dx.doi.org/10.1155/2011/931415.
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We motivate our study by simulating the particle transport of a thin film deposition process done by PVD (physical vapor deposition) processes. In this paper we present a new model taken into account a self-consistent electrostatic-particle in cell model with low density Argon plasma. The collision model are based of Monte Carlo simulations is discussed for DC sputtering in lower pressure regimes. In order to simulate transport phenomena within sputtering processes realistically, a spatial and temporal knowledge of the plasma density and electrostatic field configuration is needed. Due to relatively low plasma densities, continuum fluid equations are not applicable. We propose instead a Particle-in-cell (PIC) method, which allows the study of plasma behavior by computing the trajectories of finite-size particles under the action of an external and self-consistent electric field defined in a grid of points.
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Alhakamy, Nabil A., Shaimaa M. Badr-Eldin, Osama A. A. Ahmed, Hani Z. Asfour, Hibah M. Aldawsari, Mardi M. Algandaby, Basma G. Eid, et al. "Piceatannol-Loaded Emulsomes Exhibit Enhanced Cytostatic and Apoptotic Activities in Colon Cancer Cells." Antioxidants 9, no. 5 (May 13, 2020): 419. http://dx.doi.org/10.3390/antiox9050419.
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Piceatannol (PIC), a naturally occurring polyphenolic stilbene, has pleiotropic pharmacological activities. It has reported cytotoxic activities against different cancer cells. In the present study, PIC emulsomes (PIC-E) were formulated and assessed for cytotoxic activity. A Box–Behnken design was employed to investigate the influence of formulation factors on particle size and drug entrapment. After optimization, the formulation had a spherical shape with a particle size of 125.45 ± 1.62 nm and entrapment efficiency of 93.14% ± 2.15%. Assessment of cytotoxic activities indicated that the optimized PIC-E formula exhibited significantly lower IC50 against HCT 116 cells. Analysis of the cell cycle revealed the accumulation of cells in the G2-M phase as well as increased cell fraction in the sub-G1 phase, an indication of apoptotic-enhancing activity. Staining of cells with Annexin V indicated increased early and late apoptosis. Further, the cellular contents of caspase - 3 and Bax/Bcl-2 mRNA expression were significantly elevated by PIC-E. In addition, the mitochondrial membrane potential (MMP) was disturbed and reactive oxygen species (ROS) production was increased. In conclusion, PIC-E exhibited superior cell death-inducing activities against HCT 116 cells as compared to pure PIC. This is mediated, at least partly, by enhanced pro-apoptotic activity, disruption of MMP, and stimulation of ROS generation.
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CHUTOV, Yu I., O. Yu KRAVCHENKO, R. D. SMIRNOV, and P. P. J. M. SCHRAM. "Relaxation of dusty plasmas in plasma crystals." Journal of Plasma Physics 63, no. 1 (January 2000): 89–96. http://dx.doi.org/10.1017/s0022377899008107.
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Relaxation phenomena in two-dimensional (2D) plasma crystals have been investigated, including both the self-consistent electric charge of dust particles and the electron and ion velocity distribution functions, by means of a modified 2D particle-in-cell (PIC) method. The results obtained show that the mutual interaction of dust particles in such crystals leads to special properties of the background electrons and ions due to their selective collection by dust particles during the relaxation. These electrons and ions can behave as non-ideal components of dusty plasmas in plasma crystals even in cases where their numbers in the Debye cube are large. This effect is caused by their intensive charge exchange with dust particles, which provides dusty plasmas with the status of open statistical systems. The selective collection of electrons and ions by dust particles also causes their deviation from the initial equilibrium as well as the non-equilibrium evolution of the self-consistent electric charge of the dust particles. Relaxation phenomena in plasma crystals have to be taken into account in all cases of strong changes of plasma parameters, for example due to strong oscillations and waves in these crystals.
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Tavassoli, Arash, Mina Papahn Zadeh, Andrei Smolyakov, Magdi Shoucri, and Raymond J. Spiteri. "The electron cyclotron drift instability: A comparison of particle-in-cell and continuum Vlasov simulations." Physics of Plasmas 30, no. 3 (March 2023): 033905. http://dx.doi.org/10.1063/5.0134457.
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The linear and nonlinear characteristics of the electron cyclotron drift instability (ECDI) have been studied through the particle-in-cell (PIC) and continuum Vlasov simulation methods in connection with the effects of the azimuthal length (in the [Formula: see text] direction) on the simulations. Simulation results for a long azimuthal length (17.82 cm [Formula: see text], where ωce is the electron cyclotron frequency and vd is the E × B drift of the electrons) are reported, for which a high resolution is achieved in Fourier space. For simulations with a long azimuthal length, the linear growth rates of the PIC simulations show a considerable discrepancy with the theory, whereas the linear growth rate of the Vlasov simulations remains close to the theory. In the nonlinear regime, the inverse cascade is shown in both PIC and Vlasov simulations with a sufficiently large azimuthal length. In simulations with a short azimuthal length, however, the inverse cascade is barely observed. Instead, the PIC simulations with a short azimuthal length (0.5625 cm [Formula: see text]) show an essentially continuous nonlinear dispersion, similar to what is predicted by the ion-sound turbulence theory. It is shown that, in the PIC and Vlasov simulations, the inverse cascade coincides with the formation and merging of electron structures in phase space. This process, however, terminates differently in the PIC simulations compared with the Vlasov simulations. Larger amplitudes of ECDI fluctuations are observed in the PIC simulations compared with the Vlasov simulations, leading to an intensified electron heating and anomalous current. This suggests that the statistical noise of PIC simulations might contribute to the extreme electron heating that has been observed in previous studies.
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Kumar, Atul, and Juan F. Caneses Marin. "Kinetic simulations of collision-less plasmas in open magnetic geometries *." Plasma Physics and Controlled Fusion 64, no. 3 (January 31, 2022): 035012. http://dx.doi.org/10.1088/1361-6587/ac3dee.
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Abstract Laboratory plasmas in open magnetic geometries can be found in many different applications such as (a) scrape-of-layer (SOL) and divertor regions in toroidal confinement fusion devices, (b) linear divertor simulators, (c) plasma-based thrusters and (d) magnetic mirrors etc. A common feature of these plasma systems is the need to resolve, in addition to velocity space, at least one physical dimension (e.g. along flux lines) to capture the relevant physics. In general, this requires a kinetic treatment. Fully kinetic particle-in-cell (PIC) simulations can be applied but at the expense of large computational effort. A common way to resolve this is to use a hybrid approach: kinetic ions and fluid electrons. In the present work, the development of a hybrid PIC computational tool suitable for open magnetic geometries is described which includes (a) the effect of non-uniform magnetic fields, (b) finite fully-absorbing boundaries for the particles and (c) volumetric particle sources. Analytical expressions for the momentum transport in the paraxial limit are presented with their underlying assumptions and are used to validate the results from the PIC simulations. A general method is described to construct discrete particle distribution functions in a state of mirror-equilibrium. This method is used to obtain the initial state for the PIC simulation. Collisionless simulations in a mirror geometry are performed. The results show that the effect of magnetic compression is correctly described and momentum is conserved. The self-consistent electric field is calculated and is shown to modify the ion velocity distribution function in a manner consistent with analytic theory. Based on this analysis, the ion distribution function is understood in terms of a loss-cone distribution and an isotropic Maxwell-Boltzmann distribution driven by a volumetric plasma source. Finally, the inclusion of a Monte Carlo based Fokker-Planck collision operator is discussed in the context of future work.
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Grunwald, Joschka, and Paolo Mercorelli. "Visualization of the Plasma Frequency by means of a Particle Simulation using a Normalized Periodic Model." Journal of Physics: Conference Series 2162, no. 1 (January 1, 2022): 012016. http://dx.doi.org/10.1088/1742-6596/2162/1/012016.
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Abstract In plasmas the atoms are dissociated into ions and free electrons. Due to the high mobility of the electrons, plasmas are a vibrating medium. As a result, a plasma frequency can be determined, which is an important parameter for characterizing a material. In this study, the plasma frequency is to be visualized. For this purpose, a mathematical model will be set up to describe the electron kinetics. The electrons are briefly deflected with a force against the static ion background in order to examine the interaction between the particles in the form of electrostatic fields. The discretized equations are implemented in a numerical particle simulation to visualize the movement of the electrons. The Particle-In-Cell (PIC) method is used for this. A spatial mathematical grid is created on which the simulated particles are distributed in the cells. The equations of motion and field are then solved on this grid at different times.
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Li, Dion, Yuxi Chen, Chuanfei Dong, Liang Wang, and Gabor Toth. "Numerical study of magnetic island coalescence using magnetohydrodynamics with adaptively embedded particle-in-cell model." AIP Advances 13, no. 1 (January 1, 2023): 015126. http://dx.doi.org/10.1063/5.0122087.
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Collisionless magnetic reconnection typically requires kinetic treatment that is, in general, computationally expensive compared to fluid-based models. In this study, we use the magnetohydrodynamics with an adaptively embedded particle-in-cell (MHD-AEPIC) model to study the interaction of two magnetic flux ropes. This innovative model embeds one or more adaptive PIC regions into a global MHD simulation domain such that the kinetic treatment is only applied in regions where the kinetic physics is prominent. We compare the simulation results among three cases: (1) MHD with adaptively embedded PIC regions, (2) MHD with statically (or fixed) embedded PIC regions, and (3) a full PIC simulation. The comparison yields good agreement when analyzing their reconnection rates and magnetic island separations as well as the ion pressure tensor elements and ion agyrotropy. In order to reach good agreement among the three cases, large adaptive PIC regions are needed within the MHD domain, which indicates that the magnetic island coalescence problem is highly kinetic in nature, where the coupling between the macro-scale MHD and micro-scale kinetic physics is important.
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Wu, Hao, Zhaoyu Chen, Lin Yi, Wei Jiang, and Ya Zhang. "Note on the energy transport in capacitively coupled plasmas." Plasma Sources Science and Technology 31, no. 4 (April 1, 2022): 047001. http://dx.doi.org/10.1088/1361-6595/ac5c60.
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Abstract Particle and energy balance relations are the key to understanding the discharge in low-temperature plasmas. In this note, we derived the energy transport balances in capacitively coupled plasmas (CCPs) based on the electromagnetic theory. Then we calculated the energy transport terms in CCPs from particle-in-cell/MonteCarlo (PIC/MC) simulations, including the energy absorption, energy density, energy flow, and the energy dissipation terms, both for the particles and the field. The spatial-temporal dependant and averaged distributions of energy transport terms are shown at different pressure, demonstrating the correctness and the effectiveness of the method. This revisited method may be used to aid the studies of the electrons heating mechanism in CCP, as well as in some other plasma sources.
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Lüskow, K. F., S. Kemnitz, G. Bandelow, J. Duras, D. Kahnfeld, R. Schneider, and D. Konigorski. "Particle-in-cell Simulation Concerning Heat-flux Mitigation Using Electromagnetic Fields." PLASMA PHYSICS AND TECHNOLOGY 3, no. 3 (February 13, 2016): 110–15. http://dx.doi.org/10.14311/ppt.2016.3.110.
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The Particle-in-Cell (PIC) method was used to study heat flux mitigation experiments with argon. In the experiment it was shown that a magnetic field allows to reduce the heat flux towards a target. PIC is well-suited for plasma simulation, giving the chance to get a better basic understanding of the underlying physics. The simulation demonstrates the importance of a self-consistent neutral-plasma description to understand the effect of heat flux reduction.
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Lin, H., and C. P. Liu. "Interpolation-free particle simulation." Laser and Particle Beams 38, no. 1 (January 14, 2020): 1–7. http://dx.doi.org/10.1017/s0263034619000806.
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AbstractParticle-in-Cell (PIC) simulation is an interpolation-based method on the Newton–Maxwell (N–M) system. Its well-known drawback is its shape/interpolation functions often causing the violation of continuity equations (CEs) at mesh nodes and that of Maxwell equations (MEs) at particles' positions. Whether this drawback can be overcome by choosing/solving suitable shape/interpolation functions is of fundamental importance for the PIC simulation. Until now, these shape/interpolation functions are usually subjectively chosen and, hence, always invoke the drawback. Here, we first investigate whether these shape/interpolation functions can be self-consistently solved by considering under what condition the CEs and the MEs can be satisfied anywhere. Strict mathematical analysis reveals that strict self-consistent shape/interpolation functions are unavailable. Only few approximately self-consistent shape/interpolation functions are luckily found by some authors. This fact drives us to present another universal interpolation-free strict method on the N–M system.
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ZHOU, JUN, D. G. LIU, and C. LIAO. "Modeling and simulations of high-power microwave devices using the CHIPIC code." Journal of Plasma Physics 79, no. 1 (October 8, 2012): 69–86. http://dx.doi.org/10.1017/s0022377812000724.
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AbstractThe CHIPIC code, a fully electromagnetic particle-in-cell (PIC) code for modeling and simulations of high-power microwave (HPM) devices, is introduced in this paper. It consists of a two-dimensional (2D) code and a three-dimensional (3D) code. The 2D code can model and simulate HPM devices with symmetric structure on 2D Cartesian, cylindrical and polar grids, while the 3D code can model and simulate HPM devices on 3D Cartesian and cylindrical grids. The fields are calculated using the finite-difference time-domain scheme, and the particles are described by the PIC scheme. Various types of boundary conditions have also been implemented for different kinds of applications. In addition, the 3D code is specifically designed for high-performance modeling and computing. It uses the message passing interface and the open specifications for multiprocessing (OpenMP) for parallelization. Its parallel design ensures that it is capable of efficiently executing on a variety of architectures. In order to allow efficient use of parallel architectures, it provides automated partitioning and dynamic load balancing. Even though this code is still in development, it has successfully simulated various real-world HPM experimental devices. Simulation results on some typical HPM devices by using the CHIPIC code are given, which agree well with those obtained from some well-known PIC codes. Direction for future work is also presented.
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MO, Yongpeng, Zongqian SHI, and Shenli JIA. "Study of post-arc residual plasma dissipation process of vacuum circuit breakers based on a 2D particle-in-cell model." Plasma Science and Technology 24, no. 4 (April 1, 2022): 045401. http://dx.doi.org/10.1088/2058-6272/ac5235.
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Abstract In order to get an insight into residual plasma radial motion during the post-arc stage, a two-dimensional (2D) cylindrical particle-in-cell (PIC) model is developed. Firstly, influences of a virtual boundary condition on the residual plasma motion are studied. For purpose of validating this 2D cylindrical particle-in-cell model, a comparison between one-dimensional particle-in-cell model is also presented in this paper. Then a study about the influences of the rising rate of transient recovery voltage on the residual plasma radial motion is presented on the basis of the 2D PIC model.
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Yu, Jinqing, Xiaolin Jin, Weimin Zhou, Bin Li, and Yuqiu Gu. "High-Order Interpolation Algorithms for Charge Conservation in Particle-in-Cell Simulations." Communications in Computational Physics 13, no. 4 (April 2013): 1134–50. http://dx.doi.org/10.4208/cicp.290811.050412a.
Full textAbstract:
AbstractHigh-order interpolation algorithms for charge conservation in Particle-in-Cell (PIC) simulations are presented. The methods are valid for the case that a particle trajectory is a zigzag line. The second-order and third-order algorithms which can be applied to any even-order and odd-order are discussed in this paper, respectively. Several test simulations are performed to demonstrate their validity in two-dimensional PIC code. Compared with the simulation results of one-order, high-order algorithms have advantages in computation precision and enlarging the grid scales which reduces the CPU time.
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Selvi, S., O. Porth, B. Ripperda, F. Bacchini, L. Sironi, and R. Keppens. "Effective Resistivity in Relativistic Collisionless Reconnection." Astrophysical Journal 950, no. 2 (June 1, 2023): 169. http://dx.doi.org/10.3847/1538-4357/acd0b0.
Full textAbstract:
Abstract Magnetic reconnection can power spectacular high-energy astrophysical phenomena by producing nonthermal energy distributions in highly magnetized regions around compact objects. By means of two-dimensional fully kinetic particle-in-cell (PIC) simulations, we investigate relativistic collisionless plasmoid-mediated reconnection in magnetically dominated pair plasmas with and without a guide field. In X-points, where diverging flows result in a nondiagonal thermal pressure tensor, a finite residence time for particles gives rise to a localized collisionless effective resistivity. Here, for the first time for relativistic reconnection in a fully developed plasmoid chain, we identify the mechanisms driving the nonideal electric field using a full Ohm law by means of a statistical analysis based on our PIC simulations. We show that the nonideal electric field is predominantly driven by gradients of nongyrotropic thermal pressures. We propose a kinetic physics motivated nonuniform effective resistivity model that is negligible on global scales and becomes significant only locally in X-points. It captures the properties of collisionless reconnection with the aim of mimicking its essentials in nonideal magnetohydrodynamic descriptions. This effective resistivity model provides a viable opportunity to design physically grounded global models for reconnection-powered high-energy emission.