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1
Uhlmann, E. "DISMANTLING OF THE ICMESA TRICHLOROPHENOL PLANT." Health Physics 55, no. 6 (December 1988): 1020. http://dx.doi.org/10.1097/00004032-198812000-00036.
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Bozza-Marrubini, Marialuisa. "Three Major Disasters in Italy. Experiences of Niguarda-Ca'Granda Staff of Milan." Prehospital and Disaster Medicine 1, S1 (1985): 414–19. http://dx.doi.org/10.1017/s1049023x00045325.
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The medical and nursing staff of the Niguarda-Ca' Granda Hospital of Milano has been involved in three major disasters that occurred in Italy in the years 1976 and 1980: (1) the earthquake of May 6, 1976 in a northeastern region (Friuli); (2) the ICMESA plant explosion of July 10, 1976 in Seveso (Milano) and (3) the earthquake of November 23, 1980 in the region of Irpinia (Southern Italy).Friuli Earthquake 1976On May 7, 1976, about 12 hours after the earthquake struck, the Udine Hospital, located at about 15 km from the border of the disaster area, contacted by phone the director of the Ca' Granda Hospital in Milano, requesting a relief staff of operating room and ICU nurses. The Udine Hospital was undamaged and was overburdened by work for the surgical, orthopedic and medical treatment of the rescue victims. The staff requested was needed to relieve the exhausted local nursing staff. Extra staff was needed also to accompany ambulances with patients that, after initial triage and treatment, were evacuated to other hospitals outside the seismic area.
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Kilpua, E. K. J., A. Isavnin, A. Vourlidas, H. E. J. Koskinen, and L. Rodriguez. "On the relationship between interplanetary coronal mass ejections and magnetic clouds." Annales Geophysicae 31, no. 7 (July 23, 2013): 1251–65. http://dx.doi.org/10.5194/angeo-31-1251-2013.
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Abstract. The relationship of magnetic clouds (MCs) to interplanetary coronal mass ejections (ICMEs) is still an open issue in space research. The view that all ICMEs would originate as magnetic flux ropes has received increasing attention, although near the orbit of the Earth only about one-third of ICMEs show clear MC signatures and often the MC occupies only a portion of the more extended region showing ICME signatures. In this work we analyze 79 events between 1996 and 2009 reported in existing ICME/MC catalogs (Wind magnetic cloud list and the Richardson and Cane ICME list) using near-Earth observations by ACE (Advanced Composition Explorer) and Wind. We perform a systematic comparison of cases where ICME and MC signatures coincided and where ICME signatures extended significantly beyond the MC boundaries. We find clear differences in the characteristics of these two event types. In particular, the events where ICME signatures continued more than 6 h past the MC rear boundary had 2.7 times larger speed difference between the ICME's leading edge and the preceding solar wind, 1.4 times higher magnetic fields, 2.1 times larger widths and they experienced three times more often strong expansion than the events for which the rear boundaries coincided. The events with significant mismatch in MC and ICME boundary times were also embedded in a faster solar wind and the majority of them were observed close to the solar maximum. Our analysis shows that the sheath, the MC and the regions of ICME-related plasma in front and behind the MC have different magnetic field, plasma and charge state characteristics, thus suggesting that these regions separate already close to the Sun. Our study shows that the geometrical effect (the encounter through the CME leg and/or far from the flux rope center) does not contribute much to the observed mismatch in the MC and ICME boundary times.
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Grison, Benjamin, Jan Souček, Vratislav Krupar, David Píša, Ondrej Santolík, Ulrich Taubenschuss, and František Nĕmec. "Shock deceleration in interplanetary coronal mass ejections (ICMEs) beyond Mercury’s orbit until one AU." Journal of Space Weather and Space Climate 8 (2018): A54. http://dx.doi.org/10.1051/swsc/2018043.
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The CDPP propagation tool is used to propagate interplanetary coronal mass ejections (ICMEs) observed at Mercury by MESSENGER to various targets in the inner solar system (VEX, ACE, STEREO-A and B). The deceleration of ICME shock fronts between the orbit of Mercury and 1 AU is studied on the basis of a large dataset. We focus on the interplanetary medium far from the solor corona, to avoid the region where ICME propagation modifications in velocity and direction are the most drastic. Starting with a catalog of 61 ICMEs recorded by MESSENGER, the propagation tool predicts 36 ICME impacts with targets. ICME in situ signatures are investigated close to predicted encounter times based on velocities estimated at MESSENGER and on the default propagation tool velocity (500 km s−1). ICMEs are observed at the targets in 26 cases and interplanetary shocks (not followed by magnetic ejecta) in two cases. Comparing transit velocities between the Sun and MESSENGER ($ {\bar{v}}_{\mathrm{SunMess}}$) and between MESSENGER and the targets ($ {\bar{v}}_{\mathrm{MessTar}}$), we find an average deceleration of 170 km s−1 (28 cases). Comparing $ {\bar{v}}_{\mathrm{MessTar}}$ to the velocities at the targets (v Tar), average ICME deceleration is about 160 km s−1 (13 cases). Our results show that the ICME shock deceleration is significant beyond Mercury’s orbit. ICME shock arrival times are predicted with an average accuracy of about six hours with a standard deviation of eleven hours. Focusing on two ICMEs detected first at MESSENGER and later on by two targets illustrates our results and the variability in ICME propagations. The shock velocity of an ICME observed at MESSENGER, then at VEX and finally at STEREO-B decreases all the way. Predicting arrivals of potentially effective ICMEs is an important space weather issue. The CDPP propagation tool, in association with in situ measurements between the Sun and the Earth, can permit to update alert status of such arrivals.
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Zharkova, V., and O. Khabarova. "Additional acceleration of solar-wind particles in current sheets of the heliosphere." Annales Geophysicae 33, no. 4 (April 9, 2015): 457–70. http://dx.doi.org/10.5194/angeo-33-457-2015.
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Abstract. Particles of fast solar wind in the vicinity of the heliospheric current sheet (HCS) or in a front of interplanetary coronal mass ejections (ICMEs) often reveal very peculiar energy or velocity profiles, density distributions with double or triple peaks, and well-defined streams of electrons occurring around or far away from these events. In order to interpret the parameters of energetic particles (both ions and electrons) measured by the WIND spacecraft during the HCS crossings, a comparison of the data was carried out with 3-D particle-in-cell (PIC) simulations for the relevant magnetic topology (Zharkova and Khabarova, 2012). The simulations showed that all the observed particle-energy distributions, densities, ion peak velocities, electron pitch angles and directivities can be fitted with the same model if the heliospheric current sheet is in a status of continuous magnetic reconnection. In this paper we present further observations of the solar-wind particles being accelerated to rather higher energies while passing through the HCS and the evidence that this acceleration happens well before the appearance of the corotating interacting region (CIR), which passes through the spacecraft position hours later. We show that the measured particle characteristics (ion velocity, electron pitch angles and the distance at which electrons are turned from the HCS) are in agreement with the simulations of additional particle acceleration in a reconnecting HCS with a strong guiding field as measured by WIND. A few examples are also presented showing additional acceleration of solar-wind particles during their passage through current sheets formed in a front of ICMEs. This additional acceleration at the ICME current sheets can explain the anticorrelation of ion and electron fluxes frequently observed around the ICME's leading front. Furthermore, it may provide a plausible explanation of the appearance of bidirectional "strahls" (field-aligned most energetic suprathermal electrons) at the leading edge of ICMEs as energetic electrons generated during a magnetic reconnection at the ICME-front current sheet.
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Kilpua, E. K. J., C. O. Lee, J. G. Luhmann, and Y. Li. "Interplanetary coronal mass ejections in the near-Earth solar wind during the minimum periods following solar cycles 22 and 23." Annales Geophysicae 29, no. 8 (August 30, 2011): 1455–67. http://dx.doi.org/10.5194/angeo-29-1455-2011.
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Abstract. In this paper we examine the occurrence rates and properties of interplanetary coronal mass ejections (ICMEs) and solar activity levels during the minima following solar cycle 22 (January 1995–December 1997) and 23 (January 2007–April 2010) minima using observations from the OMNI data base. Throughout the minimum following cycle 22 the CME and ICME rates roughly tracked each other, while for the minimum following cycle 23 they diverged. During the minimum after solar cycle 23, there were large variations in the streamer belt structure. During the lowest activity period of cycle 23 (based on sunspot numbers), the ICME rate was about four times higher than during a similar activity period of cycle 22. We propose that this relatively high ICME rate may be due to CME source regions occurring at lower heliolatitudes and due to equatoward deflection of slow and weak CMEs originating from the mid- and high-heliolatitudes. The maximum magnetic fields of the ICMEs identified during the minimum following cycle 23 were ~30 % lower and their radial widths were ~15 % lower compared to the ICMEs observed during the minimum following solar cycle 22. The weak and small ICMEs may result from intrinsically weak CMEs and/or they may represent stronger CMEs that are encountered far away from the center.
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Kilpua, E. K. J., H. Hietala, H. E. J. Koskinen, D. Fontaine, and L. Turc. "Magnetic field and dynamic pressure ULF fluctuations in coronal-mass-ejection-driven sheath regions." Annales Geophysicae 31, no. 9 (September 10, 2013): 1559–67. http://dx.doi.org/10.5194/angeo-31-1559-2013.
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Abstract. Compressed sheath regions form ahead of interplanetary coronal mass ejections (ICMEs) that are sufficiently faster than the preceding solar wind. The turbulent sheath regions are important drivers of magnetospheric activity, but due to their complex internal structure, relatively little is known on the distribution of the magnetic field and plasma variations in them. In this paper we investigate ultra low frequency (ULF) fluctuations in the interplanetary magnetic field (IMF) and in dynamic pressure (Pdyn) using a superposed epoch analysis of 41 sheath regions observed during solar cycle 23. We find strongest fluctuation power near the shock and in the vicinity of the ICME leading edge. The IMF and Pdyn ULF power have different profiles within the sheath; the former is enhanced in the leading part of the sheath, while the latter is increased in the trailing part of the sheath. We also find that the ICME properties affect the level and distribution of the ULF power in sheath regions. For example, sheath regions associated with strong or fast ICMEs, or those that are crossed at intermediate distances from the center, have strongest ULF power and large variation in the power throughout the sheath region. The weaker or slower ICMEs, or those that are crossed centrally, have in general considerably weaker ULF power with relatively smooth profiles. The strong and abrupt decrease of the IMF ULF power at the ICME leading edge could be used to distinguish the ICME from the preceding sheath plasma.
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Mishra, Wageesh, Kunjal Dave, Nandita Srivastava, and Luca Teriaca. "Multipoint remote and in situ observations of interplanetary coronal mass ejection structures during 2011 and associated geomagnetic storms." Monthly Notices of the Royal Astronomical Society 506, no. 1 (July 13, 2021): 1186–97. http://dx.doi.org/10.1093/mnras/stab1721.
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ABSTRACT We present multipoint remote and in situ observations of interplanetary coronal mass ejection (ICME) structures during the year 2011. The selected ICMEs arrived at Earth on 2011 March 11 and 2011 August 6, and led to geomagnetic storms. Around the launch of these CMEs from the Sun, the coronagraphs onboard STEREO-Aand-B and SOHO enabled the CMEs to be imaged from three longitudinally separated viewpoints. We attempt to identify the in situ plasma and magnetic parameters of the ICME structures at multiple locations, for example at both STEREO spacecraft and also at the ACE/Wind spacecraft near the first Sun–Earth Lagrangian point (L1), to investigate the global configuration, interplanetary propagation, arrival times and geomagnetic response of the ICMEs. The near-Earth identified ICMEs of March 11 and August 6 formed as a result of the interaction of two successive CMEs observed in the inner corona on March 7 (for the March 11 ICME) and on August 3–4 (for the August 6 ICME). Our study suggests that the structures associated with interacting CMEs, possibly as a result of deflection or large sizes, may reach to even larger longitudinally separated locations in the heliosphere. Our multipoint in situ analysis shows that the characteristics of the same shock, propagating in a pre-conditioned medium, may be different at different longitudinal locations in the heliosphere. Similarly, multiple cuts through the same ejecta/complex ejecta, formed as a result of CME–CME interaction, are found to have inhomogeneous properties. The study highlights the difficulties in connecting the local observations of an ICME from a single in situ spacecraft to its global structures.
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Raghav, Anil N., and Zubair I. Shaikh. "The pancaking of coronal mass ejections: an in situ attestation." Monthly Notices of the Royal Astronomical Society: Letters 493, no. 1 (January 17, 2020): L16—L21. http://dx.doi.org/10.1093/mnrasl/slz187.
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ABSTRACT The interplanetary counterparts of coronal mass ejections (ICMEs) are the leading driver of severe space weather. Their morphological evolution in interplanetary space and the prediction of their arrival time at Earth are the ultimate focus of space weather studies, because of their scientific and technological effects. Several investigations in the last couple of decades have assumed that ICMEs have a circular cross-section. Moreover, various models have also been developed to understand the morphology of ICMEs based on their deformed cross-section. In fact, simulation studies have suggested that the initial circular cross-section flattens significantly during their propagation in the solar wind and this is referred to as ‘pancaking’. However, an observational verification of this phenmenon is still pending and it will eventually be the primary concern of several morphological models. Here, we report the first unambiguous observational evidence of extreme flattening of the cross-section of ICMEs, similar to pancaking, based on in situ measurements of 30 ICME events. In fact, we conclude that the cross-section of ICME flux ropes transformed into a two-dimensional planar magnetic structure. Such a deformed morphological feature not only alters the prediction of their arrival time but also has significant implications in solar-terrestrial physics, the energy budget of the heliosphere, charged particle energization, turbulence dissipation and enhanced geo-effectiveness, etc.
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Matamoros, Carolina Salas, Karl Ludwig Klein, and Gerard Trottet. "Microwave radio emissions as a proxy for coronal mass ejection speed in arrival predictions of interplanetary coronal mass ejections at 1 AU." Journal of Space Weather and Space Climate 7 (2017): A2. http://dx.doi.org/10.1051/swsc/2016038.
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The propagation of a coronal mass ejection (CME) to the Earth takes between about 15 h and several days. We explore whether observations of non-thermal microwave bursts, produced by near-relativistic electons via the gyrosynchrotron process, can be used to predict travel times of interplanetary coronal mass ejections (ICMEs) from the Sun to the Earth. In a first step, a relationship is established between the CME speed measured by the Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph (SoHO/LASCO) near the solar limb and the fluence of the microwave burst. This relationship is then employed to estimate speeds in the corona of earthward-propagating CMEs. These speeds are fed into a simple empirical interplanetary acceleration model to predict the speed and arrival time of the ICMEs at Earth. The predictions are compared with observed arrival times and with the predictions based on other proxies, including soft X-rays (SXR) and coronographic measurements. We found that CME speeds estimated from microwaves and SXR predict the ICME arrival at the Earth with absolute errors of 11 ± 7 and 9 ± 7 h, respectively. A trend to underestimate the interplanetary travel times of ICMEs was noted for both techniques. This is consistent with the fact that in most cases of our test sample, ICMEs are detected on their flanks. Although this preliminary validation was carried out on a rather small sample of events (11), we conclude that microwave proxies can provide early estimates of ICME arrivals and ICME speeds in the interplanetary space. This method is limited by the fact that not all CMEs are accompanied by non-thermal microwave bursts. But its usefulness is enhanced by the relatively simple observational setup and the observation from ground, which makes the instrumentation less vulnerable to space weather hazards.
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Malandraki, O., E. T. Sarris, and P. Trochoutsos. "Probing the magnetic topology of coronal mass ejections by means of Ulysses/HI-SCALE energetic particle observations." Annales Geophysicae 18, no. 2 (February 29, 2000): 129–40. http://dx.doi.org/10.1007/s00585-000-0129-4.
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Abstract. In this work, solar flare energetic particle fluxes (Ee ≥ 42 keV) observed by the HI-SCALE instrument onboard Ulysses, a spacecraft that is probing the heliosphere in 3-D, are utilized as diagnostics of the large-scale structure and topology of the interplanetary magnetic field (IMF) embedded within two well-identified interplanetary coronal mass ejection (ICME) structures. On the basis of the energetic solar flare particle observations firm conclusions are drawn on whether the detected ICMEs have been detached from the solar corona or are still magnetically anchored to it when they arrive at 2.5 AU. From the development of the angular distributions of the particle intensities, we have inferred that portions of the ICMEs studied consisted of both open and closed magnetic field lines. Both ICMEs present a filamentary structure comprising magnetic filaments with distinct electron anisotropy characteristics. Subsequently, we studied the evolution of the anisotropies of the energetic electrons along the magnetic field loop-like structure of one ICME and computed the characteristic decay time of the anisotropy which is a measure of the amount of scattering that the trapped electron population underwent after injection at the Sun.Key words: Interplanetary physics (energetic particles; interplanetary magnetic fields)
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Cargill, P. J., and J. M. Schmidt. "Modelling interplanetary CMEs using magnetohydrodynamic simulations." Annales Geophysicae 20, no. 7 (July 31, 2002): 879–90. http://dx.doi.org/10.5194/angeo-20-879-2002.
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Abstract. The dynamics of Interplanetary Coronal Mass Ejections (ICMEs) are discussed from the viewpoint of numerical modelling. Hydrodynamic models are shown to give a good zero-order picture of the plasma properties of ICMEs, but they cannot model the important magnetic field effects. Results from MHD simulations are shown for a number of cases of interest. It is demonstrated that the strong interaction of the ICME with the solar wind leads to the ICME and solar wind velocities being close to each other at 1 AU, despite their having very different speeds near the Sun. It is also pointed out that this interaction leads to a distortion of the ICME geometry, making cylindrical symmetry a dubious assumption for the CME field at 1 AU. In the presence of a significant solar wind magnetic field, the magnetic fields of the ICME and solar wind can reconnect with each other, leading to an ICME that has solar wind-like field lines. This effect is especially important when an ICME with the right sense of rotation propagates down the heliospheric current sheet. It is also noted that a lack of knowledge of the coronal magnetic field makes such simulations of little use in space weather forecasts that require knowledge of the ICME magnetic field strength.Key words. Interplanetary physics (interplanetary magnetic fields) Solar physics, astrophysics, and astronomy (flares and mass ejections) Space plasma physics (numerical simulation studies)
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Kilpua, E. K. J., J. Pomoell, A. Vourlidas, R. Vainio, J. Luhmann, Y. Li, P. Schroeder, A. B. Galvin, and K. Simunac. "STEREO observations of interplanetary coronal mass ejections and prominence deflection during solar minimum period." Annales Geophysicae 27, no. 12 (December 10, 2009): 4491–503. http://dx.doi.org/10.5194/angeo-27-4491-2009.
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Abstract. In this paper we study the occurrence rate and solar origin of interplanetary coronal mass ejections (ICMEs) using data from the two Solar TErrestrial RElation Observatory (STEREO) and the Wind spacecraft. We perform a statistical survey of ICMEs during the late declining phase of solar cycle 23. Observations by multiple, well-separated spacecraft show that even at the time of extremely weak solar activity a considerable number of ICMEs were present in the interplanetary medium. Soon after the beginning of the STEREO science mission in January 2007 the number of ICMEs declined to less than one ICME per month, but in late 2008 the ICME rate clearly increased at each spacecraft although no apparent increase in the number of coronal mass ejections (CMEs) occurred. We suggest that the near-ecliptic ICME rate can increase due to CMEs that have been guided towards the equator from their high-latitude source regions by the magnetic fields in the polar coronal holes. We consider two case studies to highlight the effects of the polar magnetic fields and CME deflection taking advantage of STEREO observations when the two spacecraft were in the quadrature configuration (i.e. separated by about 90 degrees). We study in detail the solar and interplanetary consequences of two CMEs that both originated from high-latitude source regions on 2 November 2008. The first CME was slow (radial speed 298 km/s) and associated with a huge polar crown prominence eruption. The CME was guided by polar coronal hole fields to the equator and it produced a clear flux rope ICME in the near-ecliptic solar wind. The second CME (radial speed 438 km/s) originated from an active region 11007 at latitude 35° N. This CME propagated clearly north of the first CME and no interplanetary consequences were identified. The two case studies suggest that slow and elongated CMEs have difficulties overcoming the straining effect of the overlying field and as a consequence they are guided by the polar coronal fields and cause in-situ effects close to the ecliptic plane. The 3-D propagation directions and CME widths obtained by using the forward modelling technique were consistent with the solar and in-situ observations.
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Lara, Alejandro, and Andrea I. Borgazzi. "Dynamics of interplanetary CMEs and associated type II bursts." Proceedings of the International Astronomical Union 4, S257 (September 2008): 287–90. http://dx.doi.org/10.1017/s1743921309029421.
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AbstractCoronal mass ejections (CMEs) are large scale structures of plasma (~1016g) and magnetic field expelled from the solar corona to the interplanetary medium. During their travel in the inner heliosphere, these “interplanetary CMEs” (ICMEs), suffer acceleration due to the interaction with the ambient solar wind. Based on hydrodynamic theory, we have developed an analytical model for the ICME transport which reproduce well the observed deceleration of fast ICMEs. In this work we present the results of the model and its application to the CME observed on May 13, 2005 and the associated interplanetary type II burst.
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Dal Lago, A., C. R. Braga, R. R. S. de Mendonca, M. Rockenbach, E. Echer, N. J. Schuch, K. Munakata, et al. "Effects of ICMEs on High Energetic Particles as Observed by the Global Muon Detector Network (GMDN)." Proceedings of the International Astronomical Union 13, S335 (July 2017): 69–74. http://dx.doi.org/10.1017/s1743921318000066.
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AbstractThe Global Muon Detector Network (GMDN) is composed by four ground cosmic ray detectors distributed around the Earth: Nagoya (Japan), Hobart (Australia), Sao Martinho da Serra (Brazil) and Kuwait city (Kuwait). The network has operated since March 2006. It has been upgraded a few times, increasing its detection area. Each detector is sensitive to muons produced by the interactions of ~50 GeV Galactic Cosmic Rays (GCR) with the Earth′s atmosphere. At these energies, GCR are known to be affected by interplanetary disturbances in the vicinity of the earth. Of special interest are the interplanetary counterparts of coronal mass ejections (ICMEs) and their driven shocks because they are known to be the main origins of geomagnetic storms. It has been observed that these ICMEs produce changes in the cosmic ray gradient, which can be measured by GMDN observations. In terms of applications for space weather, some attempts have been made to use GMDN for forecasting ICME arrival at the earth with lead times of the order of few hours. Scientific space weather studies benefit the most from the GMDN network. As an example, studies have been able to determine ICME orientation at the earth using cosmic ray gradient. Such determinations are of crucial importance for southward interplanetary magnetic field estimates, as well as ICME rotation.
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Owens, M., and P. Cargill. "Non-radial solar wind flows induced by the motion of interplanetary coronal mass ejections." Annales Geophysicae 22, no. 12 (December 22, 2004): 4397–406. http://dx.doi.org/10.5194/angeo-22-4397-2004.
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Abstract. A survey of the non-radial flows (NRFs) during nearly five years of interplanetary observations revealed the average non-radial speed of the solar wind flows to be ~30km/s, with approximately one-half of the large (>100km/s) NRFs associated with ICMEs. Conversely, the average non-radial flow speed upstream of all ICMEs is ~100km/s, with just over one-third preceded by large NRFs. These upstream flow deflections are analysed in the context of the large-scale structure of the driving ICME. We chose 5 magnetic clouds with relatively uncomplicated upstream flow deflections. Using variance analysis it was possible to infer the local axis orientation, and to qualitatively estimate the point of interception of the spacecraft with the ICME. For all 5 events the observed upstream flows were in agreement with the point of interception predicted by variance analysis. Thus we conclude that the upstream flow deflections in these events are in accord with the current concept of the large-scale structure of an ICME: a curved axial loop connected to the Sun, bounded by a curved (though not necessarily circular) cross section. Key words. Interplanetary physics (flare and stream dynamics; interplanetary magnetic fields; interplanetary shocks)
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George, Harriet, Emilia Kilpua, Adnane Osmane, Timo Asikainen, Milla M. H. Kalliokoski, Craig J. Rodger, Stepan Dubyagin, and Minna Palmroth. "Outer Van Allen belt trapped and precipitating electron flux responses to two interplanetary magnetic clouds of opposite polarity." Annales Geophysicae 38, no. 4 (August 28, 2020): 931–51. http://dx.doi.org/10.5194/angeo-38-931-2020.
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Abstract. Recently, it has been established that interplanetary coronal mass ejections (ICMEs) can dramatically affect both trapped electron fluxes in the outer radiation belt and precipitating electron fluxes lost from the belt into the atmosphere. Precipitating electron fluxes and energies can vary over a range of timescales during these events. These variations depend on the initial energy and location of the electron population and the ICME characteristics and structures. One important factor controlling electron dynamics is the magnetic field orientation within the ejecta that is an integral part of the ICME. In this study, we examine Van Allen Probes (RBSPs) and Polar Orbiting Environmental Satellites (POESs) data to explore trapped and precipitating electron fluxes during two ICMEs. The ejecta in the selected ICMEs have magnetic cloud characteristics that exhibit the opposite sense of the rotation of the north–south magnetic field component (BZ). RBSP data are used to study trapped electron fluxes in situ, while POES data are used for electron fluxes precipitating into the upper atmosphere. The trapped and precipitating electron fluxes are qualitatively analysed to understand their variation in relation to each other and to the magnetic cloud rotation during these events. Inner magnetospheric wave activity was also estimated using RBSP and Geostationary Operational Environmental Satellite (GOES) data. In each event, the largest changes in the location and magnitude of both the trapped and precipitating electron fluxes occurred during the southward portion of the magnetic cloud. Significant changes also occurred during the end of the sheath and at the sheath–ejecta boundary for the cloud with south to north magnetic field rotation, while the ICME with north to south rotation had significant changes at the end boundary of the cloud. The sense of rotation of BZ and its profile also clearly affects the coherence of the trapped and/or precipitating flux changes, timing of variations with respect to the ICME structures, and flux magnitude of different electron populations. The differing electron responses could therefore imply partly different dominant acceleration mechanisms acting on the outer radiation belt electron populations as a result of opposite magnetic cloud rotation.
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Malandraki, O. E., E. T. Sarris, and G. Tsiropoula. "Magnetic topology of coronal mass ejection events out of the ecliptic: Ulysses/HI-SCALE energetic particle observations." Annales Geophysicae 21, no. 6 (June 30, 2003): 1249–56. http://dx.doi.org/10.5194/angeo-21-1249-2003.
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Abstract. Solar energetic particle fluxes (Ee > 38 keV) observed by the ULYSSES/HI-SCALE experiment are utilized as diagnostic tracers of the large-scale structure and topology of the Interplanetary Magnetic Field (IMF) embedded within two well-identified Interplanetary Coronal Mass Ejections (ICMEs) detected at 56° and 62° south heliolatitudes by ULYSSES during the solar maximum southern high-latitude pass. On the basis of the energetic solar particle observations it is concluded that: (A) the high-latitude ICME magnetic structure observed in May 2000 causes a depression in the solar energetic electron intensities which can be accounted for by either a detached or an attached magnetic field topology for the ICME; (B) during the traversal of the out-of-ecliptic ICME event observed in July 2000 energetic electrons injected at the Sun are channeled by the ICME and propagate freely along the ICME magnetic field lines to 62° S heliolatitude.Key words. Interplanetary physics (energetic particles; interplanetary magnetic fields)
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Carcaboso, Fernando, Raúl Gómez-Herrero, Francisco Espinosa Lara, Miguel A. Hidalgo, Ignacio Cernuda, and Javier Rodríguez-Pacheco. "Characterisation of suprathermal electron pitch-angle distributions." Astronomy & Astrophysics 635 (March 2020): A79. http://dx.doi.org/10.1051/0004-6361/201936601.
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Context. Suprathermal electron pitch-angle distributions (PADs) contain substantial information about the magnetic topology of the solar wind. Their characterisation and quantification allow us to automatically identify periods showing certain characteristics. Aims. This work presents a robust automatic method for the identification and statistical study of two different types of PADs: bidirectional suprathermal electrons (BDE, often associated with closed magnetic structures) and isotropic (likely corresponding to solar-detached magnetic field lines or highly scattered electrons). Methods. Spherical harmonics were fitted to the observed suprathermal PADs of the 119–193 eV energy channel of STEREO/SWEA from March 2007 to July 2014, and they were characterised using signal processing analysis in order to identify periods of isotropic and bidirectional PADs. The characterisation has been validated by comparing the results obtained here with those of previous studies. Results. Interplanetary coronal mass ejections (ICMEs) present longer BDE periods inside the magnetic obstacles. A significant amount of BDE remain after the end of the ICME. Isotropic PADs are found in the sheath of the ICMEs, and at the post-ICME region likely due to the erosion of the magnetic field lines. Both isotropy and BDE are solar-cycle dependent. The isotropy observed by STEREO shows a nearly annual periodicity, which requires further investigation. There is also a correspondence between the number of ICMEs observed and the percentage of time showing BDE. Conclusions. A method to characterise PADs has been presented and applied to the automatic identification of two relevant distributions that are commonly observed in the solar wind, such as BDE and isotropy. Four catalogues (STEREO-A and STEREO-B for isotropic and BDE periods of at least 10 min) based on this identification are provided for future applications.
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Shaikh, Zubair I., Anil N. Raghav, Geeta Vichare, Ankush Bhaskar, and Wageesh Mishra. "Comparative statistical study of characteristics of plasma in planar and non-planar ICME sheaths during solar cycles 23 and 24." Monthly Notices of the Royal Astronomical Society 494, no. 2 (April 22, 2020): 2498–508. http://dx.doi.org/10.1093/mnras/staa783.
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ABSTRACT Planar magnetic structures (PMS) are often observed in sheath regions driven by interplanetary coronal mass ejections (ICMEs) and in corotating interaction regions (CIRs). Here, we study plasma properties statistically within planar and non-planar ICME sheath regions using in situ data from the Advanced Composition Explore (ACE) spacecraft. The study includes 420 ICME-driven sheaths from 1998–2017. We found that 146 ($\sim 35{{\ \rm per\ cent}}$) ICME-driven sheaths are planar, whereas 274 ($\sim 65{{\ \rm per\ cent}}$) are non-planar. This study found that the average plasma temperature, density, speed, plasma beta, thermal pressure and magnetic pressure are higher in planar sheaths than in non-planar sheaths. This implies that high compression plays an essential role in the formation of PMS in sheath regions. Interestingly, our analysis reveals explicitly that the strength of the southward/northward magnetic field component is almost double in planar sheath regions compared with non-planar sheath regions. This suggests that planar sheaths are more geoeffective than non-planar sheaths.
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Dave, Kunjal, Wageesh Mishra, Nandita Srivastava, and R. M. Jadhav. "Study of Interplanetary and Geomagnetic Response of Filament Associated CMEs." Proceedings of the International Astronomical Union 13, S340 (February 2018): 83–84. http://dx.doi.org/10.1017/s174392131800203x.
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AbstractIt has been established that Coronal Mass Ejections (CMEs) may have significant impact on terrestrial magnetic field and lead to space weather events. In the present study, we selected several CMEs which are associated with filament eruptions on the Sun. We attempt to identify the presence of filament material within ICME at 1AU. We discuss how different ICMEs associated with filaments lead to moderate or major geomagnetic activity on their arrival at the Earth. Our study also highlights the difficulties in identifying the filament material at 1AU within isolated and in interacting CMEs.
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Asakura, Kazunori, Hironori Matsumoto, Koki Okazaki, Tomokage Yoneyama, Hirofumi Noda, Kiyoshi Hayashida, Hiroshi Tsunemi, et al. "Suzaku detection of solar wind charge exchange emission from a variety of highly ionized ions in an interplanetary coronal mass ejection." Publications of the Astronomical Society of Japan 73, no. 3 (March 16, 2021): 504–18. http://dx.doi.org/10.1093/pasj/psab015.
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Abstract X-ray emission generated through solar-wind charge exchange (SWCX) is known to contaminate X-ray observation data, the amount of which is often significant or even dominant, particularly in the soft X-ray band, when the main target consists of comparatively weak diffuse sources, depending on the space weather during the observation. In particular, SWCX events caused by interplanetary coronal mass ejections (ICMEs) tend to be spectrally rich and to provide critical information about the metal abundance in the ICME plasma. We analyzed the SN1006 background data observed with Suzaku on 2005 September 11 shortly after an X6-class solar flare, signatures of which were separately detected together with an associated ICME. We found that the data include emission lines from a variety of highly ionized ions generated through SWCX. The relative abundances of the detected ions were found to be consistent with those in past ICME-driven SWCX events. Thus, we conclude that this event was ICME driven. In addition, we detected a sulfur xvi line for the first time as one from an SWCX emission, which suggests that it is the most spectrally rich SWCX event ever observed. We suggest that observations of ICME-driven SWCX events can provide a unique probe to study the population of highly ionized ions in the plasma, which is difficult to measure in currently available in situ observations.
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Luhmann, J. G., M. L. Mays, D. Odstrcil, Yan Li, H. Bain, C. O. Lee, C. M. S. Cohen, R. A. Mewaldt, R. A. Leske, and Y. Futaana. "Prospects for Modeling and Forecasting SEP Events with ENLIL and SEPMOD." Proceedings of the International Astronomical Union 13, S335 (July 2017): 263–67. http://dx.doi.org/10.1017/s1743921317007396.
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AbstractOne view of major Solar Energetic Particle (SEP) events is that these (proton-dominated) fluxes are accelerated in heliospheric shock sources created by Interplanetary Coronal Mass Ejections (ICMEs), and then travel mainly along interplanetary magnetic field lines connecting the shock(s) to the observer(s). This places a particular emphasis on the role of the heliospheric conditions during the event, requiring a realistic description of the latter to interpret and/or model SEP events. The well-known ENLIL heliospheric simulation with cone model generated ICME shocks is used together with the SEPMOD particle event modeling scheme to demonstrate the value of applying these concepts at multiple inner heliosphere sites.
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Lepping, R. P., and C. C. Wu. "Selection effects in identifying magnetic clouds and the importance of the closest approach parameter." Annales Geophysicae 28, no. 8 (August 18, 2010): 1539–52. http://dx.doi.org/10.5194/angeo-28-1539-2010.
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Abstract. This study is motivated by the unusually low number of magnetic clouds (MCs) that are strictly identified within interplanetary coronal mass ejections (ICMEs), as observed at 1 AU; this is usually estimated to be around 30% or lower. But a looser definition of MCs may significantly increase this percentage. Another motivation is the unexpected shape of the occurrence distribution of the observers' "closest approach distances" (measured from a MC's axis, and called CA) which drops off somewhat rapidly as |CA| (in % of MC radius) approaches 100%, based on earlier studies. We suggest, for various geometrical and physical reasons, that the |CA|-distribution should be somewhere between a uniform one and the one actually observed, and therefore the 30% estimate should be higher. So we ask, When there is a failure to identify a MC within an ICME, is it occasionally due to a large |CA| passage, making MC identification more difficult, i.e., is it due to an event selection effect? In attempting to answer this question we examine WIND data to obtain an accurate distribution of the number of MCs vs. |CA| distance, whether the event is ICME-related or not, where initially a large number of cases (N=98) are considered. This gives a frequence distribution that is far from uniform, confirming earlier studies. This along with the fact that there are many ICME identification-parameters that do not depend on |CA| suggest that, indeed an MC event selection effect may explain at least part of the low ratio of (No. MCs)/(No. ICMEs). We also show that there is an acceptable geometrical and physical consistency in the relationships for both average "normalized" magnetic field intensity change and field direction change vs. |CA| within a MC, suggesting that our estimates of |CA|, BO (magnetic field intensity on the axis), and choice of a proper "cloud coordinate" system (all needed in the analysis) are acceptably accurate. Therefore, the MC fitting model (Lepping et al., 1990) is adequate, on average, for our analysis. However, this selection effect is not likely to completely answer our original question, on the unexpected ratio of MCs to ICMEs, so we must look for other factors, such as peculiarities of CME birth conditions. As a by-product of this analysis, we determine that the first order structural effects within a MC due to its interaction with the solar wind, plus the MC's usual expansion at 1 AU (i.e., the non-force free components of the MC's field) are, on average, weakly dependent on radial distance from the MC's axis; that is, in the outer reaches of a typical MC the non-force free effects show up, but even there they are rather weak. Finally, we show that it is not likely that a MC's size distribution statistically controls the occurrence distribution of the estimated |CA|s.
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Chané, E., B. Schmieder, S. Dasso, C. Verbeke, B. Grison, P. Démoulin, and S. Poedts. "Over-expansion of a coronal mass ejection generates sub-Alfvénic plasma conditions in the solar wind at Earth." Astronomy & Astrophysics 647 (March 2021): A149. http://dx.doi.org/10.1051/0004-6361/202039867.
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Context. From May 24–25, 2002, four spacecraft located in the solar wind at about 1 astronomical unit (au) measured plasma densities one to two orders of magnitude lower than usual. The density was so low that the flow became sub-Alfvénic for four hours, and the Alfvén Mach number was as low as 0.4. Consequently, the Earth lost its bow shock, and two long Alfvén wings were generated. Aims. This is one of the lowest density events ever recorded in the solar wind at 1 au, and the least documented one. Our goal is to understand what caused the very low density. Methods. Large Angle and Spectrometric Coronagraph (LASCO) and in situ data were used to identify whether something unusual occurred that could have generated such low densities Results. The very low density was recorded inside a large interplanetary coronal mass ejection (ICME), which displayed a long, linearly declining velocity profile, typical of expanding ICMEs. We deduce a normalised radial expansion rate of 1.6. Such a strong expansion, occurring over a long period of time, implies a radial size expansion growing with the distance from the Sun to the power 1.6. This can explain a two-orders-of-magnitude drop in plasma density. Data from LASCO and the Advanced Composition Explorer show that this over-expanding ICME was travelling in the wake of a previous ICME. Conclusions. The very low densities measured in the solar wind in May 2002 were caused by the over-expansion of a large ICME. This over-expansion was made possible because the ICME was travelling in a low-density and high-velocity environment present in the wake of another ICME coming from a nearby region on the Sun and ejected only three hours previously. Such conditions are very unusual, which explains why such very low densities are almost never observed.
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Démoulin, Pascal. "Evolution of interplanetary coronal mass ejections and magnetic clouds in the heliosphere." Proceedings of the International Astronomical Union 8, S300 (June 2013): 245–54. http://dx.doi.org/10.1017/s1743921313011058.
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AbstractInterplanetary Coronal Mass Ejections (ICMEs), and more specifically Magnetic Clouds (MCs), are detected with in situ plasma and magnetic measurements. They are the continuation of the CMEs observed with imagers closer to the Sun. A review of their properties is presented with a focus on their magnetic configuration and its evolution. Many recent observations, both in situ and with imagers, point to a key role of flux ropes, a conclusion which is also supported by present coronal eruptive models. Then, is a flux rope generically present in an ICME? How to quantify its 3D physical properties when it is detected locally as a MC? Is it a simple flux rope? How does it evolve in the solar wind? This paper reviews our present answers and limited understanding to these questions.
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Richardson, J. D., Y. Liu, C. Wang, and L. F. Burlaga. "ICMES at very large distances." Advances in Space Research 38, no. 3 (January 2006): 528–34. http://dx.doi.org/10.1016/j.asr.2005.06.049.
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Kaymaz, Zerefşan, and George Siscoe. "Field-Line Draping Around ICMES." Solar Physics 239, no. 1-2 (November 30, 2006): 437–48. http://dx.doi.org/10.1007/s11207-006-0308-x.
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Wang, Jiemin, Yan Zhao, Hengqiang Feng, Qiang Liu, Zhanjun Tian, Hongbo Li, Ake Zhao, and Guoqing Zhao. "Comparison of counterstreaming suprathermal electron signatures of ICMEs with and without magnetic cloud: are all ICMEs flux ropes?" Astronomy & Astrophysics 632 (December 2019): A129. http://dx.doi.org/10.1051/0004-6361/201936733.
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Context. Magnetic clouds (MCs), as in large-scale interplanetary magnetic flux ropes, are usually still connected to the Sun at both ends near 1 AU. Many researchers believe that all nonMC interplanetary coronal mass ejections (ICMEs) also have magnetic flux rope structures, which are inconspicuous because the observing spacecraft crosses the flanks of the rope structures. If so, the field lines of nonMC ICMEs should also usually be connected to the Sun at both ends. Aims. We want to know whether or not the field lines of most nonMC ICMEs are still connected to the Sun at both ends. Methods. This study examined the counterstreaming suprathermal electron (CSE) signatures of 272 ICMEs observed by the Advanced Composition Explorer (ACE) spacecraft from 1998 to 2008 and compared the CSE signatures of MCs and nonMC ICMEs. Results. Results show that only 10 of the 101 MC events (9.9% ) and 75 of the 171 nonMC events (43.9%) have no CSEs. Moreover, 21 of the nonMC ICMEs have high CSE percentages (more than 70%) and show relatively stable magnetic field components with slight rotations, which are in line with the expectations that the observing spacecraft passes through the flank of magnetic flux ropes. Therefore, the 21 events may be magnetic flux ropes but the ACE spacecraft passes through their flanks of magnetic flux ropes. Conclusions. Considering that most other nonMC events have disordered magnetic fields, we suggest that some nonMC ICMEs inherently have disordered magnetic fields, and therefore no magnetic flux rope structures.
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Liemohn, Michael W., Matt Jazowski, Janet U. Kozyra, Natalia Ganushkina, Michelle F. Thomsen, and Joseph E. Borovsky. "CIR versus CME drivers of the ring current during intense magnetic storms." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 466, no. 2123 (May 12, 2010): 3305–28. http://dx.doi.org/10.1098/rspa.2010.0075.
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Ninety intense magnetic storms (minimum Dst value of less than −100 nT) from solar cycle 23 (1996–2005) were simulated using the hot electron and ion drift integrator (HEIDI) model. All 90 storm intervals were run with several electric fields and nightside plasma boundary conditions (five run sets). Storms were classified according to their solar wind driver, including corotating interaction regions (CIRs) and interplanetary coronal mass ejections (ICMEs). Data-model comparisons were made against the observed Dst index (specifically, Dst*) and dayside hot-ion measurements from geosynchronous orbiting spacecraft. It is found that the data-model goodness-of-fit values are different for CIR-driven storms relative to ICME-driven storms. The results are also different for the same storm category for different boundary conditions. None of the CIR-driven events was overpredicted by HEIDI, while the dayside comparisons were comparable for the different drivers. The results imply that the outer magnetosphere is responding differently to the two kinds of solar wind drivers, even though the resulting storm size might be similar. That is, for ICME-driven events, magnetospheric currents inside of geosynchronous orbit dominate the Dst perturbation, while for CIR-driven events, currents outside of this boundary have a systematically larger contribution.
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Luhmann, J. G., C. F. Dong, Y. J. Ma, S. M. Curry, Yan Li, C. O. Lee, T. Hara, et al. "Space Weather Storm Responses at Mars: Lessons from A Weakly Magnetized Terrestrial Planet." Proceedings of the International Astronomical Union 12, S328 (October 2016): 211–17. http://dx.doi.org/10.1017/s1743921317003702.
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AbstractMuch can be learned from terrestrial planets that appear to have had the potential to be habitable, but failed to realize that potential. Mars shows evidence of a once hospitable surface environment. The reasons for its current state, and in particular its thin atmosphere and dry surface, are of great interest for what they can tell us about habitable zone planet outcomes. A main goal of the MAVEN mission is to observe Mars’ atmosphere responses to solar and space weather influences, and in particular atmosphere escape related to space weather ‘storms’ caused by interplanetary coronal mass ejections (ICMEs). Numerical experiments with a data-validated MHD model suggest how the effects of an observed moderately strong ICME compare to what happens during a more extreme event. The results suggest the kinds of solar and space weather conditions that can have evolutionary importance at a planet like Mars.
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Yermolaev, Yuri I., Irina G. Lodkina, Lidia A. Dremukhina, Michael Y. Yermolaev, and Alexander A. Khokhlachev. "What Solar–Terrestrial Link Researchers Should Know about Interplanetary Drivers." Universe 7, no. 5 (May 10, 2021): 138. http://dx.doi.org/10.3390/universe7050138.
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One of the most promising methods of research in solar–terrestrial physics is the comparison of the responses of the magnetosphere–ionosphere–atmosphere system to various types of interplanetary disturbances (so-called “interplanetary drivers”). Numerous studies have shown that different types of drivers result in different reactions of the system for identical variations in the interplanetary magnetic field. In particular, the sheaths—compression regions before fast interplanetary CMEs (ICMEs)—have higher efficiency in terms of the generation of magnetic storms than ICMEs. The growing popularity of this method of research is accompanied by the growth of incorrect methodological approaches in such studies. These errors can be divided into four main classes: (i) using incorrect data with the identification of driver types published in other studies; (ii) using incorrect methods to identify the types of drivers and, as a result, misclassify the causes of magnetospheric-ionospheric disturbances; (iii) ignoring a frequent case with a complex, composite, nature of the driver (the presence of a sequence of several simple drivers) and matching the system response with only one of the drivers; for example, a magnetic storm is often generated by a sheath in front of ICME, although the authors consider these events to be a so-called “CME-induced” storm, rather than a “sheath-induced” storm; (iv) ignoring the compression regions before the fast CME in the case when there is no interplanetary shock (IS) in front of the compression region (“sheath without IS” or the so-called “lost driver”), although this type of driver generates about 10% of moderate and large magnetic storms. Possible ways of solving this problem are discussed.
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Schwenn, R., A. Dal Lago, E. Huttunen, and W. D. Gonzalez. "The association of coronal mass ejections with their effects near the Earth." Annales Geophysicae 23, no. 3 (March 30, 2005): 1033–59. http://dx.doi.org/10.5194/angeo-23-1033-2005.
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Abstract. To this day, the prediction of space weather effects near the Earth suffers from a fundamental problem: The radial propagation speed of "halo" CMEs (i.e. CMEs pointed along the Sun-Earth-line that are known to be the main drivers of space weather disturbances) towards the Earth cannot be measured directly because of the unfavorable geometry. From inspecting many limb CMEs observed by the LASCO coronagraphs on SOHO we found that there is usually a good correlation between the radial speed and the lateral expansion speed Vexp of CME clouds. This latter quantity can also be determined for earthward-pointed halo CMEs. Thus, Vexp may serve as a proxy for the otherwise inaccessible radial speed of halo CMEs. We studied this connection using data from both ends: solar data and interplanetary data obtained near the Earth, for a period from January 1997 to 15 April 2001. The data were primarily provided by the LASCO coronagraphs, plus additional information from the EIT instrument on SOHO. Solar wind data from the plasma instruments on the SOHO, ACE and Wind spacecraft were used to identify the arrivals of ICME signatures. Here, we use "ICME" as a generic term for all CME effects in interplanetary space, thus comprising not only ejecta themselves but also shocks as well. Among 181 front side or limb full or partial halo CMEs recorded by LASCO, on the one hand, and 187 ICME events registered near the Earth, on the other hand, we found 91 cases where CMEs were uniquely associated with ICME signatures in front of the Earth. Eighty ICMEs were associated with a shock, and for 75 of them both the halo expansion speed Vexp and the travel time Ttr of the shock could be determined. The function Ttr=203-20.77*ln (Vexp) fits the data best. This empirical formula can be used for predicting further ICME arrivals, with a 95% error margin of about one day. Note, though, that in 15% of comparable cases, a full or partial halo CME does not cause any ICME signature at Earth at all; every fourth partial halo CME and every sixth limb halo CME does not hit the Earth (false alarms). Furthermore, every fifth transient shock or ICME or isolated geomagnetic storm is not caused by an identifiable partial or full halo CME on the front side (missing alarms).
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Sandholt, P. E., Y. Andalsvik, and C. J. Farrugia. "Polar cap flow channel events: spontaneous and driven responses." Annales Geophysicae 28, no. 11 (November 5, 2010): 2015–25. http://dx.doi.org/10.5194/angeo-28-2015-2010.
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Abstract. We present two case studies of specific flow channel events appearing at the dusk and/or dawn polar cap boundary during passage at Earth of interplanetary (IP) coronal mass ejections (ICMEs) on 10 January and 25 July 2004. The channels of enhanced (>1 km/s) antisunward convection are documented by SuperDARN radars and dawn-dusk crossings of the polar cap by the DMSP F13 satellite. The relationship with Birkeland currents (C1–C2) located poleward of the traditional R1–R2 currents is demonstrated. The convection events are manifest in ground magnetic deflections obtained from the IMAGE (International Monitor for Auroral Geomagnetic Effects) Svalbard chain of ground magnetometer stations located within 71–76° MLAT. By combining the ionospheric convection data and the ground magnetograms we are able to study the temporal behaviour of the convection events. In the two ICME case studies the convection events belong to two different categories, i.e., directly driven and spontaneous events. In the 10 January case two sharp southward turnings of the ICME magnetic field excited corresponding convection events as detected by IMAGE and SuperDARN. We use this case to determine the ground magnetic signature of enhanced flow channel events (the NH-dusk/By<0 variant). In the 25 July case a several-hour-long interval of steady southwest ICME field (Bz<0; By<0) gave rise to a long series of spontaneous convection events as detected by IMAGE when the ground stations swept through the 12:00–18:00 MLT sector. From the ground-satellite conjunction on 25 July we infer the pulsed nature of the polar cap ionospheric flow channel events in this case. The typical duration of these convection enhancements in the polar cap is 10 min.
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Bhatt, Miral, Nandita Srivastava, and Ravindra Jadhav. "Study of Stealth CMEs and associated ICMEs." Proceedings of the International Astronomical Union 13, S340 (February 2018): 89–90. http://dx.doi.org/10.1017/s1743921318002053.
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AbstractGenerally Coronal Mass Ejections (CMEs) are large eruptions of plasma and magnetic field from the Sun into interplanetary space. CMEs are most frequently associated with a variety of phenomena occurring in the lower corona before, during and after onset of eruption and generally are visible in coronagraph observation. Stealth CMEs do not obviously exhibit any of the low-coronal signatures (LCS) like solar flares, flows, jets, coronal dimmings or brightenings, filament eruptions or the formation of flare loop arcades. In this study, five stealth CMEs are selected using LASCO/SOHO CME catalogue and associated ICMEs (Interplanetaty CMEs) are identified using data from STEREO, ACE and WIND.
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Lynnyk, A., J. Šafránková, Z. Němeček, and J. D. Richardson. "Deformation of ICMEs/MCs along their path." Planetary and Space Science 59, no. 9 (July 2011): 840–47. http://dx.doi.org/10.1016/j.pss.2011.03.016.
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Ontiveros, Veronica, and J. Americo Gonzalez-Esparza. "Geomagnetic storms caused by shocks and ICMEs." Journal of Geophysical Research: Space Physics 115, A10 (October 2010): n/a. http://dx.doi.org/10.1029/2010ja015471.
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Lepri, Susan T., and Yeimy J. Rivera. "Elemental Abundances of Prominence Material inside ICMEs." Astrophysical Journal 912, no. 1 (May 1, 2021): 51. http://dx.doi.org/10.3847/1538-4357/abea9f.
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Tancret, Franck. "Limitations of ICME and ICMS due to Variability – Alternative Strategies for Alloy Design." Materials Science Forum 783-786 (May 2014): 2213–18. http://dx.doi.org/10.4028/www.scientific.net/msf.783-786.2213.
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Integrated Computational Materials Engineering (ICME), and Integrated ComputationalMaterials Science (ICMS) are developing fields with an aim of alloy design, by combining physicalmodels describing materials behavior through lengthscales and processing steps. It has beensuspected, however, that uncertainties in input parameters may cumulate in a hereditary way andyield to a high variability in the final output, independently of the quality of models themselves.Such a variability is however rarely quantified. In this aim, an illustrative example is here given,using a set of “cascade models”, each model being voluntarily very simple (grain growth,precipitation, hardening…) whereas assumed to be exact, so that only the effect of parameteruncertainties on the variability of the output (yield stress of a Ni-base superalloy) can be studied. Itis demonstrated that, with usual uncertainty levels in input parameters, the final dispersion (error)can become very high. Additionally, considering that models are not exact themselves would renderthe situation even worse. Besides, global and implicit models, like neural networks or Gaussianprocesses, have been shown to be able to perform reliable predictions and to be used for alloydesign, with acceptable levels of error, the latter being estimated by statistical methods. In addition,unlike ICME or ICMS, predictions are very fast so that automatic alloy composition optimisation ispossible using, for instance, genetic algorithms. Other fast predictive tools, like computationalthermodynamics (Thermo-Calc), can then be used as constraints during alloy optimisation.
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Iju, T., M. Tokumaru, and K. Fujiki. "Kinematic Properties of Slow ICMEs and an Interpretation of a Modified Drag Equation for Fast and Moderate ICMEs." Solar Physics 289, no. 6 (January 23, 2014): 2157–75. http://dx.doi.org/10.1007/s11207-014-0472-3.
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Benacquista, Remi, Sandrine Rochel, and Guy Rolland. "Understanding the variability of magnetic storms caused by ICMEs." Annales Geophysicae 35, no. 1 (January 30, 2017): 147–59. http://dx.doi.org/10.5194/angeo-35-147-2017.
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Abstract. In this paper, we study the dynamics of magnetic storms due to interplanetary coronal mass ejections (ICMEs). We used multi-epoch superposed epoch analyses (SEAs) with a choice of epoch times based on the structure of the events. By sorting the events with respect to simple large-scale features (presence of a shock, magnetic structure, polarity of magnetic clouds), this method provides an original insight into understanding the variability of magnetic storm dynamics. Our results show the necessity of seeing ICMEs and their preceding sheaths as a whole since each substructure impacts the other and has an effect on its geoeffectiveness. It is shown that the presence of a shock drives the geoeffectiveness of the sheaths, while both the shock and the magnetic structure impact the geoeffectiveness of the ICMEs. In addition, we showed that the ambient solar wind characteristics are not the same for ejecta and magnetic clouds (MCs). The ambient solar wind upstream magnetic clouds are quieter than upstream ejecta and particularly slower. We also focused on the polarity of magnetic clouds since it drives not only their geoeffectiveness but also their temporal dynamics. South–north magnetic clouds (SN-MCs) and north–south magnetic clouds (NS-MCs) show no difference in geoeffectiveness for our sample of events. Lastly, since it is well-known that sequences of events can possibly induce strong magnetic storms, such sequences have been studied using superposed epoch analysis (SEA) for the first time. We found that these sequences of ICMEs are very usual and concern about 40 % of the ICMEs. Furthermore, they cause much more intense magnetic storms than isolated events do.
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Lakka, Antti, Tuija I. Pulkkinen, Andrew P. Dimmock, Emilia Kilpua, Matti Ala-Lahti, Ilja Honkonen, Minna Palmroth, and Osku Raukunen. "GUMICS-4 analysis of interplanetary coronal mass ejection impact on Earth during low and typical Mach number solar winds." Annales Geophysicae 37, no. 4 (July 11, 2019): 561–79. http://dx.doi.org/10.5194/angeo-37-561-2019.
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Abstract. We study the response of the Earth's magnetosphere to fluctuating solar wind conditions during interplanetary coronal mass ejections (ICMEs) using the Grand Unified Magnetosphere-Ionosphere Coupling Simulation (GUMICS-4). The two ICME events occurred on 15–16 July 2012 and 29–30 April 2014. During the strong 2012 event, the solar wind upstream values reached up to 35 particles cm−3, speeds of up to 694 km s−1, and an interplanetary magnetic field of up to 22 nT, giving a Mach number of 2.3. The 2014 event was a moderate one, with the corresponding upstream values of 30 particles cm−3, 320 km s−1 and 10 nT, indicating a Mach number of 5.8. We examine how the Earth's space environment dynamics evolves during both ICME events from both global and local perspectives, using well-established empirical models and in situ measurements as references. We show that on the large scale, and during moderate driving, the GUMICS-4 results are in good agreement with the reference values. However, the local values, especially during high driving, show more variation: such extreme conditions do not reproduce local measurements made deep inside the magnetosphere. The same appeared to be true when the event was run with another global simulation. The cross-polar cap potential (CPCP) saturation is shown to depend on the Alfvén–Mach number of the upstream solar wind. However, care must be taken in interpreting these results, as the CPCP is also sensitive to the simulation resolution.
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Ram, Mangey. "Papers from ICMTEA 2016." International Journal of Quality & Reliability Management 34, no. 6 (June 5, 2017): 750–51. http://dx.doi.org/10.1108/ijqrm-03-2017-0041.
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Vršnak, Bojan. "Analytical and empirical modelling of the origin and heliospheric propagation of coronal mass ejections, and space weather applications." Journal of Space Weather and Space Climate 11 (2021): 34. http://dx.doi.org/10.1051/swsc/2021012.
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The focus is on the physical background and comprehension of the origin and the heliospheric propagation of interplanetary coronal mass ejections (ICMEs), which can cause most severe geomagnetic disturbances. The paper considers mainly the analytical modelling, providing useful insight into the nature of ICMEs, complementary to that provided by numerical MHD models. It is concentrated on physical processes related to the origin of CMEs at the Sun, their heliospheric propagation, up to the effects causing geomagnetic perturbations. Finally, several analytical and statistical forecasting tools for space weather applications are described.
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Lepri, Susan T., Thomas H. Zurbuchen, Jacob R. Gruesbeck, and Jason A. Gilbert. "The in-situ manifestation of solar prominence material." Proceedings of the International Astronomical Union 8, S300 (June 2013): 289–96. http://dx.doi.org/10.1017/s1743921313011113.
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AbstractCoronal mass ejections observed in the corona exhibit a three-part structure, with a leading bright front indicating dense plasma, a low density cavity thought to be a signature of the embedded magnetic flux rope, and the high density core likely containing cold, prominence material. When observed in-situ, as Interplanetary CMEs (or ICMEs), the presence of all three of these signatures remains elusive, with the prominence material rarely observed. We report on a comprehensive and long-term search for prominence material inside ICMEs as observed by the Solar Wind Ion Composition Spectrometer on the Advanced Composition Explorer. Using a novel data analysis process, we are able to identify traces of low charge state plasma created during prominence eruptions associated with ICMEs. We find that the likelihood of occurrence of cold material in the heliosphere is vastly lower than that observed in the corona but that conditions during the eruption do allow low charge ions to make it into the solar wind, preserving their expansion history. We discuss the implications of these findings.
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Andalsvik, Y. L., P. E. Sandholt, and C. J. Farrugia. "Dayside and nightside contributions to cross-polar cap potential variations: the 20 March 2001 ICME case." Annales Geophysicae 29, no. 11 (November 29, 2011): 2189–201. http://dx.doi.org/10.5194/angeo-29-2189-2011.
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Abstract. We investigate the association between temporal-spatial structure of polar cap convection and auroral electrojet intensifications during a 5-h-long interval of strong forcing of the magnetosphere by an ICME/Magnetic cloud on 20 March 2001. We use data from coordinated ground-satellite observations in the 15:00–20:00 MLT sector. We take advantage of the good latitudinal coverage in the polar cap and in the auroral zone of the IMAGE chain of ground magnetometers in Svalbard – Scandinavia – Russia and the stable magnetic field conditions in ICMEs. The electrojet events are characterized by a sequence of 10 min-long AL excursions to −1000/−1500 nT followed by poleward expansions and auroral streamers. These events are superimposed on a high disturbance level when the AL index remains around −500 nT for several hours. These signatures are different from those appearing in classical substorms, most notably the absence of a complete recovery phase when AL usually reaches above −100 nT. We concentrate on polar cap convection in both hemispheres (DMSP F13 data) in relation to the ICME By conditions, electrojet intensifications, and the global UV auroral configuration obtained from the IMAGE spacecraft. The temporal evolution of convection properties such as the cross-polar cap potential (CPCP) drop and flow channels at the dawn/dusk polar cap (PC) boundaries around the time of the electrojet events are investigated. This approach allows us to distinguish between dayside (magnetopause reconnection) and nightside (magnetotail reconnection) sources of the PC convection events within the context of the expanding-contracting model of high-latitude convection in the Dungey cycle. Inter-hemispheric symmetries/asymmetries in the presence of newly-discovered convection channels at the dawn or dusk side PC boundaries are determined.
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Xu, Mengjiao, Chenglong Shen, Yutian Chi, Yuming Wang, Qiang Hu, Gang Li, Zhihui Zhong, and Jiayi Liu. "The Enhancement of the Energetic Particle Intensities in ICMEs." Astrophysical Journal 885, no. 1 (October 30, 2019): 54. http://dx.doi.org/10.3847/1538-4357/ab4596.
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Gazis, P. R., A. Balogh, S. Dalla, R. Decker, B. Heber, T. Horbury, A. Kilchenmann, et al. "ICMEs at High Latitudes and in the Outer Heliosphere." Space Science Reviews 123, no. 1-3 (March 2006): 417–51. http://dx.doi.org/10.1007/s11214-006-9023-z.
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Oprea, C., M. Mierla, D. Beşliu-Ionescu, O. Stere, and G. Mariş Muntean. "A study of solar and interplanetary parameters of CMEs causing major geomagnetic storms during SC 23." Annales Geophysicae 31, no. 8 (August 1, 2013): 1285–95. http://dx.doi.org/10.5194/angeo-31-1285-2013.
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Abstract. In this paper we analyse 25 Earth-directed and strongly geoeffective interplanetary coronal mass ejections (ICMEs) which occurred during solar cycle 23, using data provided by instruments on SOHO (Solar and Heliospheric Observatory), ACE (Advanced Composition Explorer) and geomagnetic stations. We also examine the in situ parameters, the energy transfer into magnetosphere, and the geomagnetic indexes. We compare observed travel times with those calculated by observed speeds projected into the plane of the sky and de-projected by a simple model. The best fit was found with the projected speeds. No correlation was found between the importance of a flare and the geomagnetic Dst (disturbance storm time) index. By comparing the in situ parameters with the Dst index we find a strong connection between some of these parameters (such as Bz, Bs · V and the energy transfer into the magnetosphere) with the strength of the geomagnetic storm. No correlation was found with proton density and plasma temperature. A superposed epoch analysis revealed a strong dependence of the Dst index on the southward component of interplanetary magnetic field, Bz, and to the Akasofu coupling function, which evaluates the energy transfer between the ICME and the magnetosphere. The analysis also showed that the geomagnetic field at higher latitudes is disturbed before the field around the Earth's equator.
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Park, Yang-Byung. "ICMESE: Intelligent consultant system for material handling equipment selection and evaluation." Journal of Manufacturing Systems 15, no. 5 (January 1996): 325–33. http://dx.doi.org/10.1016/0278-6125(96)84195-1.
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