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M B Moldwin - One of the best experts on this subject based on the ideXlab platform.
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[1] The Combined Release and Radiation Effects Satellite
2016Co-Authors: M B Moldwin, H J Singer, R. R. Anderson, Y Nishimura, K. Takahashi, V Angelopoulos, J R WygantAbstract:(CRRES) mission provides an opportunity to study the distribution of MHD wave power in the inner magneto‐ sphere both inside the high‐density plasmasphere and in the low‐density trough. We present a statistical survey of Pc5 power using CRRES magnetic field, electric field, and plasma wave data separated into plasmasphere and trough intervals. Using a database of Plasmapause crossings, we examined differences in power spectral density between the plasmasphere and trough regions. These differences were typically a factor of 3 or 4 but could be as much as an order of magnitude and could be seen in both electric and magnetic field data. Our study shows that determining the Plasmapause location is important for understanding and modeling the MHD wave environ‐ ment in the Pc5 frequency band. Citation: Hartinger, M.
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mlt dependence in the relationship between Plasmapause solar wind and geomagnetic activity based on crres 1990 1991
2016Co-Authors: Mario Bandic, Viviane Pierrard, G. Verbanac, M B Moldwin, Giovanni PireddaAbstract:Using the database of CRRES in situ observations of the Plasmapause crossings, we develop linear and more complex Plasmapause models parametrized by (a) solar wind parameters V (solar wind velocity), BV (where B is the magnitude of the interplanetary magnetic field (IMF)), and dΦmp/dt (which combines different physical mechanisms which run magnetospheric activity), and (b) geomagnetic indices Dst, Ap, and AE. The complex models are built by including a first harmonic in magnetic local time (MLT). Our method based on the cross-correlation analyses provides not only the Plasmapause shape for different levels of geomagnetic activity but additionally yields the information of the delays in the MLT response of the Plasmapause. All models based on both solar wind parameters and geomagnetic indices indicate the maximal Plasmapause extension in the postdusk side at high geomagnetic activity. The decrease in the convection electric field places the bulge toward midnight. These results are compared and discussed in regard to past works. Our study shows that the time delays in the Plasmapause response are a function of MLT and suggests that the Plasmapause is formed by the mechanism of interchange instability motion. We observed that any change quickly propagates across dawn to noon, and then at lower rate toward midnight. The results further indicate that the instability may propagate much faster during solar maximum than around solar minimum. This study contributes to the determination of the MLT dependence of the Plasmapause and to constrain physical mechanism by which the Plasmapause is formed.
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conjunction study of Plasmapause location using ground based magnetometers image euv and kaguya tex data
2010Co-Authors: Yuki Obana, Go Murakami, Ichiro Yoshikawa, I R Mann, P J Chi, M B MoldwinAbstract:[1] A statistical study comparing the Plasmapause location determined using extreme ultraviolet (EUV) and cross-phase measurements was performed over 50 days in May-July 2000 and 1 day in May 2008. In EUV images the Plasmapause location was estimated using the sharp gradient in the brightness of 30.4 nm He + emission. We have taken EUV images obtained by the IMAGE and the Kaguya satellites, which were operated in a solar maximum and minimum periods, respectively. In the ground-based cross-phase measurement, the Plasmapause was defined as a steep drop of mass density in its radial profile. Mass density was inferred from the eigenfrequency of field line resonances in the ULF band (∼1―1000 mHz), which was deduced from geomagnetic field data using cross-phase analysis. The two measurements of the Plasmapause have been compared in a same meridian at the same time and very good agreement was found in 18 of 19 events. Our result clearly indicates that the He + and mass density Plasmapause are usually detected at the same place with the error range of ± 0.4 R E . In only one event, the He + and the mass density defined Plasmapauses were not colocated. This event may be due to the difference of refilling time between He + and other dominant species.
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pc5 wave power in the quiet time plasmasphere and trough crres observations
2010Co-Authors: M D Hartinger, H J Singer, R. R. Anderson, Y Nishimura, K. Takahashi, V Angelopoulos, M B Moldwin, J R WygantAbstract:[1] The Combined Release and Radiation Effects Satellite (CRRES) mission provides an opportunity to study the distribution of MHD wave power in the inner magnetosphere both inside the high-density plasmasphere and in the low-density trough. We present a statistical survey of Pc5 power using CRRES magnetic field, electric field, and plasma wave data separated into plasmasphere and trough intervals. Using a database of Plasmapause crossings, we examined differences in power spectral density between the plasmasphere and trough regions. These differences were typically a factor of 3 or 4 but could be as much as an order of magnitude and could be seen in both electric and magnetic field data. Our study shows that determining the Plasmapause location is important for understanding and modeling the MHD wave environment in the Pc5 frequency band.
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the correlation between mid latitude trough and the Plasmapause
2005Co-Authors: Ekassie Yizengaw, M B Moldwin, Hanying Wei, David A Galvan, Lukas Mandrake, Anthony J MannucciAbstract:[1] We use simultaneous global observations of the mid-latitude trough and the Plasmapause to experimentally prove a long-standing conjecture of magnetosphere-ionosphere coupling- namely the mid-latitude trough and Plasmapause are on the same field line. Global Ionospheric Maps (GIM), generated using ground based GPS receivers, are used to detect the globally extended mid-latitude trough; while global IMAGE EUV pictures are used to estimate the Plasmapause position. Observations during the equinox and solstices and during quiet and disturbed periods are analyzed. In addition, positions of the mid-latitude trough are calculated using a simple empirical model. The two independent observations (mid-latitude trough and Plasmapause positions) and an empirical model have been compared on a global scale and found to be in excellent agreement.
J Goldstein - One of the best experts on this subject based on the ideXlab platform.
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the relationship between the Plasmapause and outer belt electrons
2016Co-Authors: J Goldstein, D N Baker, J B Blake, S De Pascuale, H O Funsten, A N Jaynes, J M Jahn, C A KletzingAbstract:Here, we quantify the spatial relationship between the Plasmapause and outer belt electrons for a 5 day period, 15–20 January 2013, by comparing locations of relativistic electron flux peaks to the Plasmapause. A peak-finding algorithm is applied to 1.8–7.7 MeV relativistic electron flux data. A Plasmapause gradient finder is applied to wave-derived electron number densities >10 cm–3. We identify two outer belts. Outer belt 1 is a stable zone of >3 MeV electrons located 1–2 RE inside the Plasmapause. Outer belt 2 is a dynamic zone of <3 MeV electrons within 0.5 RE of the moving Plasmapause. Electron fluxes earthward of each belt's peak are anticorrelated with cold plasma density. Belt 1 decayed on hiss timescales prior to a disturbance on 17 January and suffered only a modest dropout, perhaps owing to shielding by the plasmasphere. Afterward, the partially depleted belt 1 continued to decay at the initial rate. Belt 2 was emptied out by strong disturbance-time losses but restored within 24 h. For global context we use a Plasmapause test particle simulation and derive a new plasmaspheric index Fp, the fraction of a circular drift orbit inside the Plasmapause. We find that the locally measured Plasmapause is (for thismore » event) a good proxy for the globally integrated opportunity for losses in cold plasma. Our analysis of the 15–20 January 2013 time interval confirms that high-energy electron storage rings can persist for weeks or even months if prolonged quiet conditions prevail. This case study must be followed up by more general study (not limited to a 5 day period).« less
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simulation of van allen probes Plasmapause encounters
2014Co-Authors: J Goldstein, S De Pascuale, C A Kletzing, W S Kurth, K J Genestreti, R M Skoug, Bradford Larsen, L M KistlerAbstract:We use an E × B-driven Plasmapause test particle (PTP) simulation to provide global contextual information for in situ measurements by the Van Allen Probes (Radiation Belt Storm Probes (RBSP)) during 15–20 January 2013. During 120 h of simulation time beginning on 15 January, geomagnetic activity produced three plumes. The third and largest simulated plume formed during enhanced convection on 17 January, and survived as a rotating, wrapped, residual plume for tens of hours. To validate the simulation, we compare its output with RBSP data. Virtual RBSP satellites recorded 28 virtual Plasmapause encounters during 15–19 January. For 26 of 28 (92%) virtual crossings, there were corresponding actual RBSP encounters with Plasmapause density gradients. The mean difference in encounter time between model and data is 36 min. The mean model-data difference in radial location is 0.40 ± 0.05 RE. The model-data agreement is better for strong convection than for quiet or weakly disturbed conditions. On 18 January, both RBSP spacecraft crossed a tenuous, detached plasma feature at approximately the same time and nightside location as a wrapped residual plume, predicted by the model to have formed 32 h earlier on 17 January. The agreement between simulation and data indicates that the model-provided global information is adequate to correctly interpret the RBSP density observations.
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the global pattern of evolution of plasmaspheric drainage plumes
2013Co-Authors: J Goldstein, B R SandelAbstract:We present observations of an 18 June 2001 erosion event obtained by the IMAGE extreme ultraviolet (EUV) imager. Following a 0304 UT southward turning of the interplanetary magnetic field (IMF), the plasmasphere on both nightside and dayside surged sunward, reducing the plasmasphere radius on the nightside and creating a broad drainage plume on the dayside. Over several hours this plume narrowed in magnetic local time (MLT), until shortly after a northward IMF turning between 1430 UT and 1500 UT, when the plume began corotating with the Earth. On a global scale, the 18 June EUV plasma sphere observations are consistent with the interpretation that dayside magnetopause reconnection (DMR) during southward IMF produced a sunward convection field in the inner magnetosphere. Using the Volland-Stern electric potential model normalized to the solar wind E-field, we performed a simple Plasmapause test particle (PTP) simulation of the 18 June event and found good global agreement with EUV observations, but important sub-global differences as well. On a sub-global scale, proper treatment of plasmaspheric dynamics requires consideration of sub-auroral polarization streams (SAPS) and penetration electric field to explain narrow duskside plumes and preferential pre-dawn Plasmapause motion, respectively. The 18 June 2001 EUV images contain evidence of a double plume (or bifurcation of a single plume) and dayside crenulations of the Plasmapause, both of which remain unexplained. The observations suggest that strong convection suppresses or smooths Plasmapause structure, which tends to increase during times of weak or absent convection. Analysis of the motion of the Plasmapause on 18 June 2001 reveals some ofthe details of the initial erosion process, which apparently involves partial indentation of the Plasmapause and subsequent widening of this indentation to other MLT sectors eastward and westward of the initial indentation, and produces 'rotated V' signatures in the electric field. Early erosion on 18 June was bursty, and modulated by the solar wind electric field; convection was turned on during southward IMF and turned off during northward IMF. Northward IMF apparently triggered overshielding, causing the formation of a midnight-to-dawn Plasmapause bulge that subsequently corotated. It is clear that more detailed information about the inner magnetospheric E-field is required to fully understand plasmaspheric dynamics.
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Role of the plasmasphere in radiation belt particle energization and loss from DMSP, IMAGE, and SAMPEX observations
2012Co-Authors: W. R. Johnston, J Goldstein, P. C. Anderson, T. P. O’brien, S. G. KanekalAbstract:The Plasmapause is very dynamic in response to changes in magnetospheric convection and other stormtime phenomena. The outer radiation belt is also dynamic during stormtime in terms of both radial location and energetic particle population. It is proposed that outer radiation belt particles are variously depleted and energized due to wave-particle interactions associated with the Plasmapause location. This may be tested by simultaneous observations of energetic particles and the Plasmapause location. SAMPEX observations of radiation belt particles may be compared with Plasmapause observations from IMAGE, but these provide limited temporal coverage. We use data from DMSP satellites to identify the Plasmapause signature in the ionosphere (specifically the light ion trough) to provide more continuous Plasmapause observations. This will allow us to build a multiyear database of Plasmapause locations. We report on comparisons of these DMSP-derived Plasmapause locations to IMAGE-based observations as well as SAMPEX observations of outer radiation belt dynamics and precipitating particle microbursts. Fig. 1. Convection paths for plasma in magnetosphere, which are along equipotentials of the superposition of the corotation and solar-wind driven electric fields. Within the Plasmapause, flux tube motion is dominated by corotation; outside this boundary motion is dominated by convection. Duskside bulge is evident. (From Kavanagh et al., 1968) The evolution of the Plasmapause during active times can significantly affect the outer radiation belt: • Summers et al. (1998) argue that enhanced electromagnetic ion cyclotron (EMIC) waves within the plasmasphere tend to scatter trapped electrons into the loss cone, depleting radiation belt particles inside the Plasmapause. At the same time, outside the Plasmapause whistler-mode waves tend to energize trappe
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ground magnetometer observation of a cross phase reversal at a steep Plasmapause
2007Co-Authors: Z C Kale, J Goldstein, C. L. Waters, I R Mann, F W Menk, L G OzekeAbstract:[1] The cross-phase technique employs ground-based magnetometer data in order to determine the resonance frequency of a geomagnetic field line. Typically, a positive cross-phase maximum identifies the field line resonance frequency, but occasionally, a negative cross-phase maximum is observed and is believed to be a feature of the steep density gradient at the Plasmapause. For a few hours during the local morning of 14 May 2001 the cross-phase maximum, observed using two pairs of ground-based magnetometer stations from the European sector, with midpoints at L = 3.16 and L = 3.34, reversed polarity from positive to negative. All other British Geological Survey, Sub-Auroral Magnetometer Network, and International Monitor for Auroral Geomagnetic Effects (IMAGE) magnetometer array station pairs examined between L = 2.39 and L = 6.54 showed a positive cross-phase maximum throughout the day. The Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) satellite made an excellent close magnetic conjunction with these ground-based magnetometer arrays on this day, and data from the IMAGE Radio Plasma Imager instrument show a very steep Plasmapause in this region during this UT interval. IMAGE Extreme Ultraviolet Imager global plasmasphere images show that the Plasmapause moved outward through the day, passing through the region of the observed negative cross-phase maxima. This rare observation of a negative cross-phase maximum occurs at the location of a Plasmapause with a gradient steeper than r−8 and thus is in agreement with theory. The two cross-phase peak polarity reversals are explained by the evolution of the local density profile.
Mark A Clilverd - One of the best experts on this subject based on the ideXlab platform.
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1 POES Satellite Observations of EMIC-wave driven Relativistic Electron Precipitation during 1998-2010
2016Co-Authors: Bonar R Carson, Craig J. Rodger, Mark A ClilverdAbstract:Abstract. Using six satellites that have carried the SEM-2 instrument package, a total of 436,422 individual half orbits between 1998 and 2010 were inspected by an automatic detection algorithm searching for EMIC-driven relativistic electron precipitation (REP). The algorithm searched for one of the key characteristics of EMIC-driven REP, identified as the simultaneity between spikes in the P1 (52 keV differential proton flux channel) and P6 (>800 keV electron channel). In all, 2,331 proton precipitation associated REP (PPAREP) events were identified. The majority of events were observed at L-values within the outer radiation belt (3<L<7) and were more common in the dusk and night sectors as determined by MLT. The majority of events occurred outside the plasmasphere, at L-values ~1 Re greater than the Plasmapause location determined from two different statistical models. The events make up a subset of EMIC-driven proton spikes investigated by Sandanger et al. [2009], and potentially reflect different overall characteristics compared with proton spikes, particularly when comparing their location to that of the Plasmapause, i.e., EMIC-driven proton precipitation inside the Plasmapause, and potentially EMIC-driven REP outside the Plasmapause. There was no clear relationship between the location of plasmaspheric plumes and the locations of the PPAREP events detected. Analysis of the PPAREP event occurrence indicates that high sola
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remote sensing the plasmasphere Plasmapause plumes and other features using ground based magnetometers
2014Co-Authors: F W Menk, Mark A Clilverd, C. L. Waters, Z C Kale, M D Sciffer, P W Robinson, R S Grew, I R MannAbstract:The Plasmapause is a highly dynamic boundary between different magnetospheric particle populations and convection regimes. Some of the most important space weather processes involve wave-particle interactions in this region, but wave properties may also be used to remote sense the plasmasphere and Plasmapause, contributing to plasmasphere models. This paper discusses the use of existing ground magnetometer arrays for such remote sensing. Using case studies we illustrate measurement of Plasmapause location, shape and movement during storms; refilling of flux tubes within and outside the plasmasphere; storm-time increase in heavy ion concentration near the Plasmapause; and detection and mapping of density irregularities near the Plasmapause, including drainage plumes, biteouts and bulges. We also use a 2D MHD model of wave propagation through the magnetosphere, incorporating a realistic ionosphere boundary and Alfven speed profile, to simulate ground array observations of power and cross-phase spectra, hence confirming the signatures of plumes and other density structures.
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characteristics of precipitating energetic electron fluxes relative to the Plasmapause during geomagnetic storms
2014Co-Authors: I Whittaker, Mark A Clilverd, Craig J. RodgerAbstract:In this study we investigate the link between precipitating electrons from the Van Allen radiation belts and the dynamical Plasmapause. We consider electron precipitation observations from the Polar Orbiting Environmental Satellite (POES) constellation during geomagnetic storms. Superposed epoch analysis is performed on precipitating electron observations for the 13 year period of 1999 to 2012 in two magnetic local time (MLT) sectors, morning and afternoon. We assume that the precipitation is due to wave-particle interactions and our two MLT sectors focus on chorus (outside the Plasmapause) and plasmaspheric hiss (inside the Plasmapause) waves. We generate simple expressions based on the geomagnetic index, Dst, which reproduce the chorus-driven observations for the >30 keV precipitating electron flux magnitudes. Additionally, we find expressions for the fitted spectral index to describe the flux variation with energy, allowing a full energy reproduction as a function of distance from the Plasmapause. The hiss-driven precipitating flux occurs inside the Plasmapause but is independent of distance from the Plasmapause. In the POES observations the hiss-induced electron precipitation is only detectable above the instrument noise in the >300 keV and P6 (>800 keV) channels of the flux detection instrument. We have derived expressions for the storm time variation in flux inside the Plasmapause using Dst as a proxy. The observations show that there is little evidence for >800 keV electron precipitation occurring outside of the Plasmapause, in the MLT sectors studied.
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poes satellite observations of emic wave driven relativistic electron precipitation during 1998 2010
2013Co-Authors: Bonar R Carson, Craig J. Rodger, Mark A ClilverdAbstract:[1] Using six Polar Orbiting Environmental Satellites (POES) satellites that have carried the Space Environment Module-2 instrument package, a total of 436,422 individual half-orbits between 1998 and 2010 were inspected by an automatic detection algorithm searching for electromagnetic ion cyclotron (EMIC) driven relativistic electron precipitation (REP). The algorithm searched for one of the key characteristics of EMIC-driven REP, identified as the simultaneity between spikes in the P1 (52 keV differential proton flux channel) and P6 (>800 keV electron channel). In all, 2331 proton precipitation associated REP (PPAREP) events were identified. The majority of events were observed at L-values within the outer radiation belt (3 < L < 7) and were more common in the dusk and night sectors as determined by magnetic local time. The majority of events occurred outside the plasmasphere, at L-values ~1 Re greater than the Plasmapause location determined from two different statistical models. The events make up a subset of EMIC-driven proton spikes investigated by Sandanger et al. (2009), and potentially reflect different overall characteristics compared with proton spikes, particularly when comparing their location to that of the Plasmapause, i.e., EMIC-driven proton precipitation inside the Plasmapause, and potentially EMIC-driven REP outside the Plasmapause. There was no clear relationship between the location of plasmaspheric plumes and the locations of the PPAREP events detected. Analysis of the PPAREP event occurrence indicates that high solar wind speed and high geomagnetic activity levels increase the likelihood of an event being detected. The peak PPAREP event occurrence was during the declining phase of solar cycle 23, consistent with the 2003 maximum in the geomagnetic activity index, Ap.
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poes satellite observations of emic wave driven relativistic electron precipitation during 1998 2010
2013Co-Authors: Bonar R Carson, Craig J. Rodger, Mark A ClilverdAbstract:[1] Using six Polar Orbiting Environmental Satellites (POES) satellites that have carried the Space Environment Module-2 instrument package, a total of 436,422 individual half-orbits between 1998 and 2010 were inspected by an automatic detection algorithm searching for electromagnetic ion cyclotron (EMIC) driven relativistic electron precipitation (REP). The algorithm searched for one of the key characteristics of EMIC-driven REP, identified as the simultaneity between spikes in the P1 (52 keV differential proton flux channel) and P6 (>800 keV electron channel). In all, 2331 proton precipitation associated REP (PPAREP) events were identified. The majority of events were observed at L-values within the outer radiation belt (3 < L < 7) and were more common in the dusk and night sectors as determined by magnetic local time. The majority of events occurred outside the plasmasphere, at L-values ~1 Re greater than the Plasmapause location determined from two different statistical models. The events make up a subset of EMIC-driven proton spikes investigated by Sandanger et al. (2009), and potentially reflect different overall characteristics compared with proton spikes, particularly when comparing their location to that of the Plasmapause, i.e., EMIC-driven proton precipitation inside the Plasmapause, and potentially EMIC-driven REP outside the Plasmapause. There was no clear relationship between the location of plasmaspheric plumes and the locations of the PPAREP events detected. Analysis of the PPAREP event occurrence indicates that high solar wind speed and high geomagnetic activity levels increase the likelihood of an event being detected. The peak PPAREP event occurrence was during the declining phase of solar cycle 23, consistent with the 2003 maximum in the geomagnetic activity index, Ap.
Viviane Pierrard - One of the best experts on this subject based on the ideXlab platform.
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relationship between global Plasmapause characteristics and Plasmapause structures in the frame of interchange instability mechanism
2020Co-Authors: Mario Bandic, Viviane Pierrard, G. VerbanacAbstract:Recent studies based on CLUSTER, CRRES, and especially on THEMIS satellite data have revealed the statistical behavior of the global Plasmapause such as eastward azimuthal Plasmapause propagation and radial Plasmapause motion between 21 and 07 magnetic local times (MLTs) most likely at postmidnight. The results are shown to be in a good agreement with characteristics of the Plasmapause modeled using interchange instability mechanism. The present study is based on the Plasmapause modeled with the mentioned physical mechanism, and it aims to link the observed global Plasmapause dynamic with formation and evolution of Plasmapause structures. We investigated two Plasmapause datasets obtained using real Kp values and certain type of time‐dependent changes in the Kp (thereafter Kp jumps) as input in the simulations. The Kp jumps include sharp Kp increase, sharp Kp decrease, short‐time burst enhancement (increase‐decrease within 3 hr) in Kp, and their combinations in order to obtain plumes, shoulders, and notches, the structures most often observed in the nature. The cross‐correlation analyses is applied to the modeled Plasmapause and to the geomagnetic Kp index at different 1‐hr MLT bins. We have shown that the cross‐correlation curves provide deeper insight in the physical processes related to the Plasmapause dynamic and evolution. Their behavior is interpreted as the imprint of the Plasmapause structure passages through specific MLT sector. Taking into account that the Plasmapause in the single events shows very complex and different behaviors, the most important finding of the present study is the simple explanation of what causes global Plasmapause motions and deformation in time.
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mlt Plasmapause characteristics comparison between themis observations and numerical simulations
2018Co-Authors: G. Verbanac, Viviane Pierrard, Mario Bandic, Junghee ChoAbstract:We perform a statistical comparison of the global behavior of the THEMIS observed and simulated Plasmapause in the geomagnetic equatorial plane. Simulation is based on the interchange instability mechanism. Analyzing Plasmapause positions (LPPs) from the period July 2008 to December 2012, we derived formation and propagation characteristics of the main Plasmapause, which reflect the most probable global Plasmapause behavior. The results suggest a global eastward azimuthal Plasmapause propagation and a radial Plasmapause motion limited to the 21–07 MLT sector. The formation of the Plasmapause takes place with the highest probability at postmidnight. It is likely that the erosion occurs in a range of MLTs simultaneously. On the dayside, the Plasmapause moves almost entirely azimuthally. We suggest that the Plasmapause propagates azimuthally with a mean angular velocity close to the corotation speed at all MLTs, at least during periods of lower geomagnetic activity. The results also show that the experimental Plasmapause characteristics are in accordance with the interchange instability mechanism. Along with the proposed suggestions for future works, this study contributes to making a further step toward resolving some of the long‐lasting, unresolved issues related to Plasmapause dynamics.
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evidence of mlt propagation of the Plasmapause inferred from themis data
2017Co-Authors: Mario Bandic, Viviane Pierrard, G. Verbanac, Junghee ChoAbstract:Abstract The cross-correlation analysis is applied to the comprehensive database of THEMIS Plasmapause crossings (6840 LPP s) and both solar wind parameters and geomagnetic indices (thereafter LPP indicators). We estimate MLTs of the Plasmapause formation and further monitor the motion of the new Plasmapause at high MLT resolution. Our results show that Plasmapause is firstly formed within 23–07 MLT and then propagates around the Earth with the velocity estimated to amounts for 1.10 and 0.45 of the corotation velocity in sectors 07–15 MLT and 15–23 MLT, respectively. Two branches within 23–07 MLT are identified, one at low time lags (Tlag s) and second at high Tlag s which we relate to the formation of the new Plasmapause and to the propagation of the Plasmapause formed one MLT-cycle before. This study can be used to improve the current understanding of the Plasmapause formation and propagation.
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mlt dependence in the relationship between Plasmapause solar wind and geomagnetic activity based on crres 1990 1991
2016Co-Authors: Mario Bandic, Viviane Pierrard, G. Verbanac, M B Moldwin, Giovanni PireddaAbstract:Using the database of CRRES in situ observations of the Plasmapause crossings, we develop linear and more complex Plasmapause models parametrized by (a) solar wind parameters V (solar wind velocity), BV (where B is the magnitude of the interplanetary magnetic field (IMF)), and dΦmp/dt (which combines different physical mechanisms which run magnetospheric activity), and (b) geomagnetic indices Dst, Ap, and AE. The complex models are built by including a first harmonic in magnetic local time (MLT). Our method based on the cross-correlation analyses provides not only the Plasmapause shape for different levels of geomagnetic activity but additionally yields the information of the delays in the MLT response of the Plasmapause. All models based on both solar wind parameters and geomagnetic indices indicate the maximal Plasmapause extension in the postdusk side at high geomagnetic activity. The decrease in the convection electric field places the bulge toward midnight. These results are compared and discussed in regard to past works. Our study shows that the time delays in the Plasmapause response are a function of MLT and suggests that the Plasmapause is formed by the mechanism of interchange instability motion. We observed that any change quickly propagates across dawn to noon, and then at lower rate toward midnight. The results further indicate that the instability may propagate much faster during solar maximum than around solar minimum. This study contributes to the determination of the MLT dependence of the Plasmapause and to constrain physical mechanism by which the Plasmapause is formed.
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The relationship between Plasmapause, solar wind and geomagnetic activity between 2007 and 2011
2015Co-Authors: G. Verbanac, Viviane Pierrard, M. Bandić, F. Darrouzet, Jean-louis Rauch, Pierrette DécréauAbstract:Taking advantage of the Cluster satellite mission and especially the observations made by the instrument WHISPER to deduce the electron number density along the orbit of the satellites, we studied the relationships between the Plasmapause positions (L-PP) and the following L-PP indicators: (a) solar wind coupling functions B-z (Z component of the interplanetary magnetic field vector, B, in GSM system), BV (related to the interplanetary electric field; B is the magnitude of the interplanetary magnetic field vector, V is solar wind velocity), and d phi(mp)/dt (which combines different physical processes responsible for the magnetospheric activity) and (b) geomagnetic indices Dst, Ap and AE. The analysis is performed separately for three magnetic local time (MLT) sectors (Sector1 - night sector (01:00-07:00 MLT); Sector2 - day sector (07:00-16:00 MLT); Sector3 - evening sector (16:00-01:00 MLT)) and for all MLTs taken together. All L-PP indicators suggest the faster Plasmapause response in the postmidnight sector. Delays in the Plasmapause responses (hereafter time lags) are approximately 2-27 h, always increasing from Sector1 to Sector3. The obtained fits clearly resolve the MLT structures. The variability in the Plasmapause is the largest for low values of L-PP indicators, especially in Sector2. At low activity levels, L-PP exhibits the largest values on the dayside (in Sector2) and the smallest on the postmidnight side (Sector1). Displacements towards larger values on the evening side (Sector3) and towards lower values on the dayside (Sector2) are identified for enhanced magnetic activity. Our results contribute to constraining the physical mechanisms involved in the Plasmapause formation and to further study the still not well understood related issues.
R. R. Anderson - One of the best experts on this subject based on the ideXlab platform.
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[1] The Combined Release and Radiation Effects Satellite
2016Co-Authors: M B Moldwin, H J Singer, R. R. Anderson, Y Nishimura, K. Takahashi, V Angelopoulos, J R WygantAbstract:(CRRES) mission provides an opportunity to study the distribution of MHD wave power in the inner magneto‐ sphere both inside the high‐density plasmasphere and in the low‐density trough. We present a statistical survey of Pc5 power using CRRES magnetic field, electric field, and plasma wave data separated into plasmasphere and trough intervals. Using a database of Plasmapause crossings, we examined differences in power spectral density between the plasmasphere and trough regions. These differences were typically a factor of 3 or 4 but could be as much as an order of magnitude and could be seen in both electric and magnetic field data. Our study shows that determining the Plasmapause location is important for understanding and modeling the MHD wave environ‐ ment in the Pc5 frequency band. Citation: Hartinger, M.
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pc5 wave power in the quiet time plasmasphere and trough crres observations
2010Co-Authors: M D Hartinger, H J Singer, R. R. Anderson, Y Nishimura, K. Takahashi, V Angelopoulos, M B Moldwin, J R WygantAbstract:[1] The Combined Release and Radiation Effects Satellite (CRRES) mission provides an opportunity to study the distribution of MHD wave power in the inner magnetosphere both inside the high-density plasmasphere and in the low-density trough. We present a statistical survey of Pc5 power using CRRES magnetic field, electric field, and plasma wave data separated into plasmasphere and trough intervals. Using a database of Plasmapause crossings, we examined differences in power spectral density between the plasmasphere and trough regions. These differences were typically a factor of 3 or 4 but could be as much as an order of magnitude and could be seen in both electric and magnetic field data. Our study shows that determining the Plasmapause location is important for understanding and modeling the MHD wave environment in the Pc5 frequency band.
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pc5 wave power in the quiet time plasmasphere and trough crres observations
2010Co-Authors: M D Hartinger, Vassilis Angelopoulos, Mark B. Moldwin, H J Singer, R. R. Anderson, Y Nishimura, K. Takahashi, John R WygantAbstract:[1] The Combined Release and Radiation Effects Satellite (CRRES) mission provides an opportunity to study the distribution of MHD wave power in the inner magnetosphere both inside the high-density plasmasphere and in the low-density trough. We present a statistical survey of Pc5 power using CRRES magnetic field, electric field, and plasma wave data separated into plasmasphere and trough intervals. Using a database of Plasmapause crossings, we examined differences in power spectral density between the plasmasphere and trough regions. These differences were typically a factor of 3 or 4 but could be as much as an order of magnitude and could be seen in both electric and magnetic field data. Our study shows that determining the Plasmapause location is important for understanding and modeling the MHD wave environment in the Pc5 frequency band.
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plasmaspheric plumes crres observations of enhanced density beyond the Plasmapause
2004Co-Authors: M B Moldwin, R. R. Anderson, H K Rassoul, J Howard, Jeff Sanny, J D BocchicchioAbstract:[1] CRRES plasma wave receiver density data were used to study the distribution and properties of dense plasmaspheric-like plasma observed outside the Plasmapause. Our study indicates that outer plasmaspheric structure, often called plasmaspheric plumes, blobs, tails, or detached plasma regions, can exist at all local times under all levels of geomagnetic activity. Of the 558 CRRES orbits that had at least one clearly defined Plasmapause, 169 (or 30%) had plasmaspheric-like density structures at higher L shells than the Plasmapause. Most of the occurrences of plasmaspheric-like plasma observed by CRRES were in the noon-to-dusk sector in the aftermath of enhanced geomagnetic activity consistent with plasmaspheric plume models.
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Plasmapause response to geomagnetic storms crres results
2003Co-Authors: M B Moldwin, S S Mayerberger, H K Rassoul, T Barnicki, R. R. AndersonAbstract:[1] The response of the Plasmapause following a geomagnetic storm is examined statistically using Plasmapause observations made by the Combined Release and Radiation Effects Satellite (CRRES) plasma wave receiver instrument. The Plasmapause was identified as the inner most steep density gradient. Due to CRRES' 10-hour orbital period, the Plasmapause is generally sampled at two distinct local time sectors each orbit. The results from a study of 22 storms (with minimum Dst < −30 nT) show that the Plasmapause generally moves earthward one L in the night and dawnside following a storm sudden commencement but is highly variable and statistically moves out in the dusk sector. This new result emphasizes that the Plasmapause can have significant local time asymmetries that are amplified due to storm dynamics.