Bibliography



Found 42 entries in the Bibliography.


Showing entries from 1 through 42


2020

Global ENA Imaging and In Situ Observations of Substorm Dipolarization on 10 August 2016

Abstract This paper presents the first combined use of data from Magnetospheric Multiscale (MMS), Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS), and Van Allen Probes (RBSP) to study the 10 August 2016 magnetic dipolarization. We report the first correlation of MMS tail observations with TWINS energetic neutral atom (ENA) images of the ring current (RC). We analyze 15-min, 1° TWINS 2 images in 1–50 keV energy bins. To characterize the high-altitude RC we extract peak ENA flux from L= 2.5 to 5 in the postmid ...

Goldstein, J.; Valek, P.; McComas, D.; Redfern, J.; Spence, H.; Skoug, R.; Larsen, B.; Reeves, G.; Nakamura, R.;

YEAR: 2020     DOI: 10.1029/2019JA027733

substorm dipolarization; cross-scale physics; imaging; multipoint in situ; ring current; Van Allen Probes

Evolutions of equatorial ring current ions during a magnetic storm

In this paper, we present evolutions of the phase space density (PSD) spectra of ring current (RC) ions based on observations made by Van Allen Probe B during a geomagnetic storm on 23–24 August 2016. By analyzing PSD spectra ratios from the initial phase to the main phase of the storm, we find that during the main phase, RC ions with low magnetic moment μ values can penetrate deeper into the magnetosphere than can those with high μ values, and that the μ range of PSD enhancement meets the relationship: S(O+) > S(He+) > ...

Huang, Zheng; Yuan, Zhigang; Yu, Xiongdong;

YEAR: 2020     DOI: 10.26464/epp2020019

ULF waves; ring current; wave-particle interactions; Radial Transport; Geomagnetic storm; Decay rates; Van Allen Probes

2019

Eastward Propagating Second Harmonic Poloidal Waves Triggered by Temporary Outward Gradient of Proton Phase Space Density: Van Allen Probe A Observation

Two wave packets of second harmonic poloidal Pc 4 waves with a wave frequency of ~7 mHz were detected by Van Allen Probe A at a radial distance of ~5.8 RE and magnetic local time of 13 hr near the magnetic equator, where plasmaspheric refilling was in progress. Proton butterfly distributions with energy dispersions were also measured at the same time; the proton fluxes at 10-30 keV oscillated with the same frequency as the Pc 4 waves. Using the ion sounding technique, we find that the Pc 4 waves propagated eastward with an a ...

Yamamoto, K.; e, Nos\; Keika, K.; Hartley, D.P.; Smith, C.W.; MacDowall, R.J.; Lanzerotti, L.J.; Mitchell, D.G.; Spence, H.E.; Reeves, G.D.; Wygant, J.R.; Bonnell, J.W.; Oimatsu, S.;

YEAR: 2019     DOI: 10.1029/2019JA027158

drift-bounce resonance; Geomagnetic storm; plasmasphere; ring current; substorm; ULF wave; Van Allen Probes

Substorm-Ring Current Coupling: A Comparison of Isolated and Compound Substorms

Substorms are a highly variable process, which can occur as an isolated event or as part of a sequence of multiple substorms (compound substorms). In this study we identify how the low-energy population of the ring current and subsequent energization varies for isolated substorms compared to the first substorm of a compound event. Using observations of H+ and O+ ions (1 eV to 50 keV) from the Helium Oxygen Proton Electron instrument onboard Van Allen Probe A, we determine the energy content of the ring current in L-MLT space ...

Sandhu, J.; Rae, I.; Freeman, M.; Gkioulidou, M.; Forsyth, C.; Reeves, G.; Murphy, K.; Walach, M.-T.;

YEAR: 2019     DOI: 10.1029/2019JA026766

inner magnetosphere; ring current; substorms; Van Allen; Van Allen Probes

Ion Heating by Electromagnetic Ion Cyclotron Waves and Magnetosonic Waves in the Earth\textquoterights Inner Magnetosphere

Electromagnetic ion cyclotron (EMIC) waves and magnetosonic waves are commonly observed in the Earth\textquoterights magnetosphere associated with enhanced ring current activity. Using wave and ion measurements from the Van Allen Probes, we identify clear correlations between the hydrogen- and helium-band EMIC waves with the enhancement of trapped helium and oxygen ion fluxes, respectively. We calculate the diffusion coefficients of different ion species using quasi-linear theory to understand the effects of resonant scatter ...

Ma, Q.; Li, W.; Yue, C.; Thorne, R.; Bortnik, J.; Kletzing, C.; Kurth, W.; Hospodarsky, G.; Reeves, G.; Spence, H.;

YEAR: 2019     DOI: 10.1029/2019GL083513

electromagnetic ion cyclotron waves; Ion heating; Quasilinear modeling; Resonant interaction in plasmasphere; ring current; Van Allen Probes; Van Allen Probes observation

Quenching of Equatorial Magnetosonic Waves by Substorm Proton Injections

Near equatorial (fast) magnetosonic waves, characterized by high magnetic compressibility, are whistler-mode emissions destabilized by proton shell/ring distributions. In the past, substorm proton injections are widely known to intensify magnetosonic waves in the inner magnetosphere. Here we report the unexpected observations by the Van Allen Probes of the magnetosonic wave quenching associated with the substorm proton injections under both high- and low-density conditions. The enhanced proton thermal pressure distorted the ...

Dai, Guyue; Su, Zhenpeng; Liu, Nigang; Wang, Bin; Zheng, Huinan; Wang, Yuming; Wang, Shui;

YEAR: 2019     DOI: 10.1029/2019GL082944

Bernstein mode instability; magnetosonic wave; Radiation belt; ring current; substorm injection; Van Allen Probes; Wave-particle interaction

Reanalysis of Ring Current Electron Phase Space Densities Using Van Allen Probe Observations, Convection Model, and Log-Normal Kalman Filter

Aseev, N.; . Y. Shprits, Y;

YEAR: 2019     DOI: 10.1029/2018SW002110

data assimilation; inner magnetosphere; Kalman Filter; Reanalysis; ring current; Van Allen Probes

Reanalysis of ring current electron phase space densities using Van Allen Probe observations, convection model, and log-normal Kalman filter

Models of ring current electron dynamics unavoidably contain uncertainties in boundary conditions, electric and magnetic fields, electron scattering rates, and plasmapause location. Model errors can accumulate with time and result in significant deviations of model predictions from observations. Data assimilation offers useful tools which can combine physics-based models and measurements to improve model predictions. In this study, we systematically analyze performance of the Kalman filter applied to a log-transformed convec ...

Aseev, N.A.; Shprits, Y.Y.;

YEAR: 2019     DOI: 10.1029/2018SW002110

data assimilation; inner magnetosphere; Kalman Filter; Reanalysis; ring current; Van Allen Probes

Statistical Study of Selective Oxygen Increase in High-Energy Ring Current Ions During Magnetic Storms

Ion transport from the plasma sheet to the ring current is the main cause of the development of the ring current. Energetic (>150 keV) ring current ions are known to be transported diffusively in several days. A recent study suggested that energetic oxygen ions are transported closer to the Earth than protons due to the diffusive transport caused by a combination of the drift and drift-bounce resonances with Pc 3\textendash5 ultralow frequency waves during the 24 April 2013 magnetic storm. To understand the occurrence condit ...

Mitani, K.; Seki, K.; Keika, K.; Gkioulidou, M.; Lanzerotti, L.; Mitchell, D.; Kletzing, C.; Yoshikawa, A.; Obana, Y.;

YEAR: 2019     DOI: 10.1029/2018JA026168

Magnetic Storms; Oxygen ions; ring current; Van Allen Probes

2018

Precipitation of radiation belt electrons by EMIC waves with conjugated observations of NOAA and Van Allen satellites

In this letter, we present unique conjugated satellite observations of MeV relativistic electron precipitation caused by electromagnetic ion cyclotron (EMIC) waves. On the outer boundary of the plasmasphere, the Van Allen probe observed EMIC waves. At ionospheric altitudes, the NOAA 16 satellite at the footprint of Van Allen probe simultaneously detected obvious flux enhancements for precipitating >MeV radiation belt electrons, but not for precipitating

Yuan, Zhigang; Liu, Kun; Yu, Xiongdong; Yao, Fei; Huang, Shiyong; Wang, Dedong; Ouyang, Zhihai;

YEAR: 2018     DOI: 10.1029/2018GL080481

Chorus; EMIC waves; Particle precipitation; Radiation belt; ring current; Van Allen Probes; Wave-particle interaction

Energisation of the ring current by substorms

The substorm process releases large amounts of energy into the magnetospheric system, although where the energy is transferred to and how it is partitioned remains an open question. In this study, we address whether the substorm process contributes a significant amount of energy to the ring current. The ring current is a highly variable region, and understanding the energisation processes provides valuable insight into how substorm - ring current coupling may contribute to the generation of storm conditions and provide a sou ...

Sandhu, J.; Rae, I.; Freeman, M.; Forsyth, C.; Gkioulidou, M.; Reeves, G.; Spence, H.; Jackman, C.; Lam, M.;

YEAR: 2018     DOI: 10.1029/2018JA025766

BSPICE; HOPE; Magnetosphere; ring current; substorms; Van Allen Probes

Magnetosonic harmonic falling and rising frequency emissions potentially generated by nonlinear wave-wave interactions in the Van Allen radiation belts

Magnetosonic waves play a potentially important role in the complex evolution of the radiation belt electrons. These waves typically appear as discrete emission lines along the proton gyrofrequency harmonics, consistent with the prediction of the local Bernstein mode instability of hot proton ring distributions. Magnetosonic waves are nearly dispersionless particularly at low harmonics and therefore have the roughly unchanged frequency-time structures during the propagation. On the basis of Van Allen Probes observations, we ...

Liu, Nigang; Su, Zhenpeng; Zheng, Huinan; Wang, Yuming; Wang, Shui;

YEAR: 2018     DOI: 10.1029/2018GL079232

Bernstein mode instability; magnetosonic wave; Radiation belt; ring current; rising/falling frequency; Van Allen Probes; wave propagation

Ion Trapping and Acceleration at Dipolarization Fronts: High-Resolution MHD/Test-Particle Simulations

Much of plasma heating and transport from the magnetotail into the inner magnetosphere occurs in the form of mesoscale discrete injections associated with sharp dipolarizations of magnetic field (dipolarization fronts). In this paper we investigate the role of magnetic trapping in acceleration and transport of the plasmasheet ions into the ring current. For this purpose we use high-resolution global MHD and three-dimensional test-particle simulations. It is shown that trapping, produced by sharp magnetic field gradients at t ...

. Y. Ukhorskiy, A; Sorathia, K.; Merkin, V.; Sitnov, M.; Mitchell, D.; Gkioulidou, M.;

YEAR: 2018     DOI: 10.1029/2018JA025370

injections; plasma pressure; ring current; trapping; Van Allen Probes

Radial Transport of Higher-Energy Oxygen Ions Into the Deep Inner Magnetosphere Observed by Van Allen Probes

The transport mechanism of the ring current ions differs among ion energies. Lower-energy (≲150 keV) ions are well known to be transported convectively. Higher-energy (≳150 keV) protons are reported to be transported diffusively, while there are few reports about transport of higher-energy oxygen ions. We report the radial transport of higher-energy oxygen ions into the deep inner magnetosphere during the late main phase of the magnetic storm on 23\textendash25 April 2013 observed by the Van Allen Probes spacecraft. An e ...

Mitani, K.; Seki, K.; Keika, K.; Gkioulidou, M.; Lanzerotti, L.; Mitchell, D.; Kletzing, C.;

YEAR: 2018     DOI: 10.1029/2018GL077500

magnetic storm; oxygen ion; ring current; Van Allen Probes

Prompt Disappearance and Emergence of Radiation Belt Magnetosonic Waves Induced by Solar Wind Dynamic Pressure Variations

Magnetosonic waves are highly oblique whistler mode emissions transferring energy from the ring current protons to the radiation belt electrons in the inner magnetosphere. Here we present the first report of prompt disappearance and emergence of magnetosonic waves induced by the solar wind dynamic pressure variations. The solar wind dynamic pressure reduction caused the magnetosphere expansion, adiabatically decelerated the ring current protons for the Bernstein mode instability, and produced the prompt disappearance of magn ...

Liu, Nigang; Su, Zhenpeng; Zheng, Huinan; Wang, Yuming; Wang, Shui;

YEAR: 2018     DOI: 10.1002/2017GL076382

magnetosonic waves; Radiation belt; ring current; solar wind dynamic pressure; Van Allen Probes; Wave-particle interaction

2017

Ring Current He-Ion Control by Bounce Resonant ULF Waves

Ring current energy He-ion (\~65 keV to \~520 keV) differential flux data from the Radiation Belt Storm Probe Ion Composition Experiment (RBSPICE) instrument aboard the Van Allan Probes spacecraft show considerable variability during quiet solar wind and geomagnetic time periods. Such variability is apparent from orbit to orbit (\~9 hours) of the spacecraft and is observed to be \~50\textendash100\% of the nominal flux. Using data from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) instrume ...

Kim, Hyomin; Gerrard, Andrew; Lanzerotti, Louis; Soto-Chavez, Rualdo; Cohen, Ross; Manweiler, Jerry;

YEAR: 2017     DOI: 10.1002/2017JA023958

bounce resonance; Helium ion; ring current; ULF waves; Van Allen Probes

The characteristic pitch angle distributions of 1 eV to 600 keV protons near the equator based on Van Allen Probes observations

Understanding the source and loss processes of various plasma populations is greatly aided by having accurate knowledge of their pitch angle distributions (PADs). Here, we statistically analyze ~1 eV to 600 keV hydrogen (H+) PADs near the geomagnetic equator in the inner magnetosphere based on Van Allen Probes measurements, to comprehensively investigate how the H+ PADs vary with different energies, magnetic local times (MLTs), L-shells, and geomagnetic conditions. Our survey clearly indicates four distinct populations with ...

Yue, Chao; Bortnik, Jacob; Thorne, Richard; Ma, Qianli; An, Xin; Chappell, C.; Gerrard, Andrew; Lanzerotti, Louis; Shi, Quanqi; Reeves, Geoffrey; Spence, Harlan; Mitchell, Donald; Gkioulidou, Matina; Kletzing, Craig;

YEAR: 2017     DOI: 10.1002/2017JA024421

bi-directional field-aligned; H+ Pitch angle distributions; plasmaspheric H+; radiation belt H+; ring current; Van Allen Probes; warm Plasma cloak

Relativistic electron\textquoterights butterfly pitch angle distribution modulated by localized background magnetic field perturbation driven by hot ring current ions

Dayside modulated relativistic electron\textquoterights butterfly pitch angle distributions (PADs) from \~200 keV to 2.6 MeV were observed by Van Allen Probe B at L = 5.3 on 15 November 2013. They were associated with localized magnetic dip driven by hot ring current ion (60\textendash100 keV proton and 60\textendash200 keV helium and oxygen) injections. We reproduce the electron\textquoterights butterfly PADs at satellite\textquoterights location using test particle simulation. The simulation results illustrate that a negat ...

Xiong, Ying; Chen, Lunjin; Xie, Lun; Fu, Suiyan; Xia, Zhiyang; Pu, Zuyin;

YEAR: 2017     DOI: 10.1002/2017GL072558

butterfly distribution; Radiation belt; ring current; Van Allen Probes

Ion acceleration at dipolarization fronts in the inner magnetosphere

During geomagnetic storms plasma pressure in the inner magnetosphere is controlled by energetic ions of tens to hundreds of keV. Plasma pressure is the source of global storm time currents, which control the distribution of magnetic field and couple the inner magnetosphere and the ionosphere. Recent analysis showed that the buildup of hot ion population in the inner magnetosphere largely occurs in the form of localized discrete injections associated with sharp dipolarizations of magnetic field, similar to dipolarization fron ...

. Y. Ukhorskiy, A; Sitnov, M.; Merkin, V.; Gkioulidou, M.; Mitchell, D.;

YEAR: 2017     DOI: 10.1002/2016JA023304

injections; ring current; trapping; Van Allen Probes

Acceleration at Dipolarization Fronts in the Inner Magnetosphere

During geomagnetic storms plasma pressure in the inner magnetosphere is controlled by energetic ions of tens to hundreds keV. Plasma pressure is the source of global storm-time currents, which control the distribution of magnetic field and couple the inner magnetosphere and the ionosphere. Recent analysis showed that the buildup of hot ion population in the inner magnetosphere largely occurs in the form of localized discrete injections associated with sharp dipolarizations of magnetic field, similar to dipolarization fronts ...

. Y. Ukhorskiy, A; Sitnov, M.; Merkin, V.; Gkioulidou, M.; Mitchell, D.;

YEAR: 2017     DOI: 10.1002/2016ja023304

injections; ring current; trapping; Van Allen Probes

2016

Ion nose spectral structures observed by the Van Allen Probes

We present a statistical study of nose-like structures observed in energetic hydrogen, helium, and oxygen ions near the inner edge of the plasma sheet. Nose structures are spectral features named after the characteristic shapes of energy bands or gaps in the energy-time spectrograms of in situ measured ion fluxes. Using 22 months of observations from the Helium Oxygen Proton Electron (HOPE) instrument onboard Van Allen Probe A, we determine the number of noses observed, and the minimum L-shell reached and energy of each nose ...

Ferradas, C.; Zhang, J.-C.; Spence, H.; Kistler, L.; Larsen, B.; Reeves, G.; Skoug, R.; Funsten, H.;

YEAR: 2016     DOI: 10.1002/2016JA022942

inner magnetosphere; ion injection; Ion structure; plasma sheet; ring current; Van Allen Probes

Ring Current Pressure Estimation with RAM-SCB using Data Assimilation and Van Allen Probe Flux Data

Capturing and subsequently modeling the influence of tail plasma injections on the inner magnetosphere is important for understanding the formation and evolution of the ring current. In this study, the ring current distribution is estimated with the Ring Current-Atmosphere Interactions Model with Self-Consistent Magnetic field (RAM-SCB) using, for the first time, data assimilation techniques and particle flux data from the Van Allen Probes. The state of the ring current within the RAM-SCB model is corrected via an ensemble b ...

Godinez, Humberto; Yu, Yiqun; Lawrence, Eric; Henderson, Michael; Larsen, Brian; Jordanova, Vania;

YEAR: 2016     DOI: 10.1002/2016GL071646

data assimilation; ring current; Van Allen Probes

The Source of O + in the Storm-time Ring Current

A stretched and compressed geomagnetic field occurred during the main phase of a geomagnetic storm on 1 June 2013. During the storm the Van Allen Probes spacecraft made measurements of the plasma sheet boundary layer, and observed large fluxes of O+ ions streaming up the field line from the nightside auroral region. Prior to the storm main phase there was an increase in the hot (>1 keV) and more isotropic O+ions in the plasma sheet. In the spacecraft inbound pass through the ring current region during the storm main phase, t ...

Kistler, L.M.; Mouikis, C.; Spence, H.E.; Menz, A.M.; Skoug, R.M.; Funsten, H.O.; Larsen, B.A.; Mitchell, D.G.; Gkioulidou, M.; Wygant, J.R.; Lanzerotti, L.J.;

YEAR: 2016     DOI: 10.1002/2015JA022204

Geomagnetic storm; Ionosphere; oxygen; plasma sheet; Plasma Sources; ring current; Van Allen Probes

Driving ionospheric outflows and magnetospheric O + energy density with Alfv\ en waves

We show how dispersive Alfv\ en waves observed in the inner magnetosphere during geomagnetic storms can extract O+ ions from the topside ionosphere and accelerate these ions to energies exceeding 50 keV in the equatorial plane. This occurs through wave trapping, a variant of \textquotedblleftshock\textquotedblright surfing, and stochastic ion acceleration. These processes in combination with the mirror force drive field-aligned beams of outflowing ionospheric ions into the equatorial plane that evolve to provide energetic O+ ...

Chaston, C.; Bonnell, J.; Reeves, G.; Skoug, R.;

YEAR: 2016     DOI: 10.1002/2016GL069008

Alfven waves; ion acceleration; Ionosphere; ionospheric outflow; ring current

Storm-time dynamics of ring current protons: Implications for the long-term energy budget in the inner magnetosphere

Our investigation of the long-term ring current proton pressure evolution in Earth\textquoterights inner magnetosphere based on Van Allen Probes data shows drastically different behavior of the low- and high- energy components of the ring current proton population with respect to theSYM-H index variation. We found that while the low-energy component of the protons (<80 keV) is strongly governed by convective timescales and is very well correlated with the absolute value of SYM-H index, the high-energy component (>100 keV) va ...

Gkioulidou, Matina; Ukhorskiy, A.; Mitchell, D.; Lanzerotti, L.;

YEAR: 2016     DOI: 10.1002/2016GL068013

energy budget; Geomagnetic storms; inner magnetosphere; ring current; Van Allen Probes

Ring current electron dynamics during geomagnetic storms based on the Van Allen Probes measurements

Based on comprehensive measurements from Helium, Oxygen, Proton, and Electron Mass Spectrometer Ion Spectrometer, Relativistic Electron-Proton Telescope, and Radiation Belt Storm Probes Ion Composition Experiment instruments on the Van Allen Probes, comparative studies of ring current electrons and ions are performed and the role of energetic electrons in the ring current dynamics is investigated. The deep injections of tens to hundreds of keV electrons and tens of keV protons into the inner magnetosphere occur frequently; a ...

Zhao, H.; Li, X.; Baker, D.; Claudepierre, S.; Fennell, J.; Blake, J.; Larsen, B.; Skoug, R.; Funsten, H.; Friedel, R.; Reeves, G.; Spence, H.; Mitchell, D.; Lanzerotti, L.;

YEAR: 2016     DOI: 10.1002/2016JA022358

deep injections; Geomagnetic storms; ring current; ring current energy content; ring current electrons; Van Allen Probes

Storm-time dynamics of ring current protons: Implications for the long-term energy budget in the inner magnetosphere

Our investigation of the long-term ring current proton pressure evolution in Earth\textquoterights inner magnetosphere based on Van Allen Probes data shows drastically different behavior of the low- and high- energy components of the ring current proton population with respect to the Sym-H index variation. We found that while the low-energy component of the protons (<80 keV) is strongly governed by convective timescales and is very well correlated with the absolute value of Sym-H index, the high-energy component (>100 keV) v ...

Gkioulidou, Matina; Ukhorskiy, A.; Mitchell, D.; Lanzerotti, L.;

YEAR: 2016     DOI: 10.1002/2016GL068013

energy budget; Geomagnetic storms; inner magnetosphere; ring current; Van Allen Probes

2015

Heavy-ion dominance near Cluster perigees

Time periods in which heavy ions dominate over H+ in the energy range of 1-40 keV were observed by the Cluster Ion Spectrometry (CIS)/COmposition DIstribution Function (CODIF) instrument onboard Cluster Spacecraft 4 at L-values less than 4. The characteristic feature is a narrow flux peak at around 10 keV that extends into low L-values, with He+ and/or O+ dominating. In the present work we perform a statistical study of these events and examine their temporal occurrence and spatial distribution. The observed features, both t ...

Ferradas, C.; Zhang, J.-C.; Kistler, L.; Spence, H.;

YEAR: 2015     DOI: 10.1002/2015JA021063

charge exchange; Cluster; heavy ions; inner magnetosphere; plasma sheet; ring current

Broadband low frequency electromagnetic waves in the inner magnetosphere

A prominent yet largely unrecognized feature of the inner magnetosphere associated with particle injections, and more generally geomagnetic storms, is the occurrence of broadband electromagnetic field fluctuations over spacecraft frame frequencies (fsc) extending from effectively zero to fsc ≳ 100 Hz. Using observations from the Van Allen Probes we show that these waves most commonly occur pre-midnight but are observed over a range of local times extending into the dayside magnetosphere. We find that the variation of magne ...

Chaston, C.; Bonnell, J.; Kletzing, C.; Hospodarsky, G.; Wygant, J.; Smith, C.;

YEAR: 2015     DOI: 10.1002/2015JA021690

Alfven waves; Geomagnetic storms; ring current; turbulence; Van Allen Probes

Combined Convective and Diffusive Simulations: VERB-4D Comparison with March 17, 2013 Van Allen Probes Observations

This study is focused on understanding the coupling between different electron populations in the inner magnetosphere and the various physical processes that determine evolution of electron fluxes at different energies. Observations during the March 17, 2013 storm and simulations with a newly developed Versatile Electron Radiation Belt-4D (VERB-4D) are presented. Analysis of the drift trajectories of the energetic and relativistic electrons shows that electron trajectories at transitional energies with a first invariant on t ...

Shprits, Yuri; Kellerman, Adam; Drozdov, Alexander; Spense, Harlan; Reeves, Geoffrey; Baker, Daniel;

YEAR: 2015     DOI: 10.1002/2015GL065230

inner magnetosphere; numerical simulations; Radiation belts; ring current; Van Allen Probes; wave-particle interactions

Storm-time occurrence and Spatial distribution of Pc4 poloidal ULF waves in the inner magnetosphere: A Van Allen Probes Statistical study

Poloidal ULF waves are capable of efficiently interacting with energetic particles in the ring current and the radiation belt. Using Van Allen Probes (RBSP) data from October 2012 to July 2014, we investigate the spatial distribution and storm-time occurrence of Pc4 (7-25 mHz) poloidal waves in the inner magnetosphere. Pc4 poloidal waves are sorted into two categories: waves with and without significant magnetic compressional components. Two types of poloidal waves have comparable occurrence rates, both of which are much hig ...

Dai, Lei; Takahashi, Kazue; Lysak, Robert; Wang, Chi; Wygant, John; Kletzing, Craig; Bonnell, John; Cattell, Cynthia; Smith, Charles; MacDowall, Robert; Thaller, Scott; Breneman, Aaron; Tang, Xiangwei; Tao, Xin; Chen, Lunjin;

YEAR: 2015     DOI: 10.1002/2015JA021134

Geomagnetic storm; Pc4 ULF waves; poloidal waves; ring current; solar wind dynamic pressure; Van Allen Probes

Van Allen Probes investigation of the large scale duskward electric field and its role in ring current formation and plasmasphere erosion in the June 1, 2013 storm

Using the Van Allen Probes we investigate the enhancement in the large scale duskward convection electric field during the geomagnetic storm (Dst ~ -120 nT) on June 1, 2013 and its role in ring current ion transport and energization, and plasmasphere erosion. During this storm, enhancements of ~1-2 mV/m in the duskward electric field in the co-rotating frame are observed down to L shells as low as ~2.3. A simple model consisting of a dipole magnetic field and constant, azimuthally westward, electric field is used to calculat ...

Thaller, S.; Wygant, J.; Dai, L.; Breneman, A.W.; Kersten, K.; Cattell, C.A.; Bonnell, J.W.; Fennell, J.F.; Gkioulidou, Matina; Kletzing, C.A.; De Pascuale, S.; Hospodarsky, G.B.; Bounds, S.;

YEAR: 2015     DOI: 10.1002/2014JA020875

electric field; inner magnetosphere; plasma convection; plasmasphere; ring current; Van Allen Probes

Bounce- and MLT-averaged diffusion coefficients in a physics-based magnetic field geometry obtained from RAM-SCB for the 17 March 2013 storm

Local acceleration via whistler wave and particle interaction plays a significant role in particle dynamics in the radiation belt. In this work we explore gyroresonant wave-particle interaction and quasi-linear diffusion in different magnetic field configurations related to the 17 March 2013 storm. We consider the Earth\textquoterights magnetic dipole field as a reference and compare the results against nondipole field configurations corresponding to quiet and stormy conditions. The latter are obtained with the ring current- ...

Zhao, Lei; Yu, Yiqun; Delzanno, Gian; Jordanova, Vania;

YEAR: 2015     DOI: 10.1002/2014JA020858

diffusion coefficients; Radiation belt; ring current

Global Storm-Time Depletion of the Outer Electron Belt

The outer radiation belt consists of relativistic (>0.5 MeV) electrons trapped on closed trajectories around Earth where the magnetic field is nearly dipolar. During increased geomagnetic activity, electron intensities in the belt can vary by ordersof magnitude at different spatial and temporal scale. The main phase of geomagnetic storms often produces deep depletions of electron intensities over broad regions of the outer belt. Previous studies identified three possible processes that can contribute to the main-phase deplet ...

. Y. Ukhorskiy, A; Sitnov, M.; Millan, R.; Kress, B.; Fennell, J.; Claudepierre, S.; Barnes, R.;

YEAR: 2015     DOI: 10.1002/2014JA020645

dropout; Geomagnetic storms; magnetopause loss; Radial Transport; Radiation belt; ring current; Van Allen Probes

Formation of the oxygen torus in the inner magnetosphere: Van Allen Probes observations

We study the formation process of an oxygen torus during the 12\textendash15 November 2012 magnetic storm, using the magnetic field and plasma wave data obtained by Van Allen Probes. We estimate the local plasma mass density (ρL) and the local electron number density (neL) from the resonant frequencies of standing Alfv\ en waves and the upper hybrid resonance band. The average ion mass (M) can be calculated by M \~ ρL/neL under the assumption of quasi-neutrality of plasma. During the storm recovery phase, both Probe A and ...

e, Nos\; Oimatsu, S.; Keika, K.; Kletzing, C.; Kurth, W.; De Pascuale, S.; Smith, C.; MacDowall, R.; Nakano, S.; Reeves, G.; Spence, H.; Larsen, B.;

YEAR: 2015     DOI: 10.1002/2014JA020593

inner magnetosphere; magnetic storm; oxygen torus; plasmasphere; ring current; ULF waves; Van Allen Probes

Empirical modeling of the storm-time innermost magnetosphere using Van Allen Probes and THEMIS data: Eastward and banana currents

The structure of storm-time currents in the inner magnetosphere, including its innermost region inside 4RE, is studied for the first time using a modification of the empirical geomagnetic field model TS07D and new data from Van Allen Probes and THEMIS missions. It is shown that the model, which uses basis-function expansions instead of ad hoc current modules to approximate the magnetic field, consistently improves its resolution and magnetic field reconstruction with the increase of the number of basis functions and resolves ...

Stephens, G.; Sitnov, M.; . Y. Ukhorskiy, A; Roelof, E.; Tsyganenko, N.; Le, G.;

YEAR: 2015     DOI: 10.1002/2015JA021700

eastward current; empirical geomagnetic field; magnetic storm; ring current; Van Allen Probes

2014

Comparative Investigation of the Energetic Ion Spectra Comprising the Magnetospheric Ring Currents of the Solar System

Investigated here are factors that control the intensities and shapes of energetic ion spectra that make up the ring current populations of the strongly magnetized planets of the solar system, specifically those of Earth, Jupiter, Saturn, Uranus, and Neptune. Following a previous and similar comparative investigation of radiation belt electrons, we here turn our attention to ions. Specifically, we examine the possible role of the differential ion Kennel-Petschek limit, as moderated by Electromagnetic Ion Cyclotron (EMIC) wav ...

Mauk, B.;

YEAR: 2014     DOI: 10.1002/2014JA020392

Ion Spectra; Magnetic Storms; Planetary magnetospheres; ring current; Van Allen Probes

The Comprehensive Inner Magnetosphere-Ionosphere Model

Simulation studies of the Earth\textquoterights radiation belts and ring current are very useful in understanding the acceleration, transport, and loss of energetic particles. Recently, the Comprehensive Ring Current Model (CRCM) and the Radiation Belt Environment (RBE) model were merged to form a Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model. CIMI solves for many essential quantities in the inner magnetosphere, including ion and electron distributions in the ring current and radiation belts, plasmaspheric densit ...

Fok, M.-C.; . Y. Buzulukova, N; Chen, S.-H.; Glocer, A.; Nagai, T.; Valek, P.; Perez, J.;

YEAR: 2014     DOI: 10.1002/jgra.v119.910.1002/2014JA020239

inner magnetosphere; magnetosphere-ionosphere coupling; ring current; Radiation belts; Van Allen Probes

Model of electromagnetic ion cyclotron waves in the inner magnetosphere

The evolution of He+-mode electromagnetic ion cyclotron (EMIC) waves is studied inside the geostationary orbit using our global model of ring current (RC) ions, electric field, plasmasphere, and EMIC waves. In contrast to the approach previously used by Gamayunov et al. (2009), however, we do not use the bounce-averaged wave kinetic equation but instead use a complete, nonbounce-averaged, equation to model the evolution of EMIC wave power spectral density, including off-equatorial wave dynamics. The major results of our stud ...

Gamayunov, K.; Engebretson, M.; Zhang, M.; Rassoul, H.;

YEAR: 2014     DOI: 10.1002/jgra.v119.910.1002/2014JA020032

electromagnetic ion cyclotron waves; outer radiation belt; ring current

The role of small-scale ion injections in the buildup of Earth\textquoterights ring current pressure: Van Allen Probes observations of the March 17 th , 2013 storm

Energetic particle transport into the inner magnetosphere during geomagnetic storms is responsible for significant plasma pressure enhancement, which is the driver of large-scale currents that control the global electrodynamics within the magnetosphere-ionosphere system. Therefore, understanding the transport of plasma from the tail deep into the near-Earth magnetosphere, as well as the energization processes associated with this transport, is essential for a comprehensive knowledge of the near-Earth space environment. Durin ...

Gkioulidou, Matina; Ukhorskiy, A.; Mitchell, D.; Sotirelis, T.; Mauk, B.; Lanzerotti, L.;

YEAR: 2014     DOI: 10.1002/2014JA020096

Geomagnetic storms; Ion injections; ring current; Van Allen Probes

Magnetosonic wave excitation by ion ring distributions in the Earth\textquoterights inner magnetosphere

Combining Time History of Events and Macroscale Interaction during Substorms (THEMIS) wave and particle observations and a quantitative calculation of linear wave growth rate, we demonstrate that magnetosonic (MS) waves can be locally excited by ion ring distributions in the Earth\textquoterights magnetosphere when the ion ring energy is comparable to the local Alfven energy. MS waves in association with ion ring distributions were observed by THEMIS A on 24 November 2010 in the afternoon sector, both outside the plasmapause ...

Ma, Qianli; Li, Wen; Chen, Lunjin; Thorne, Richard; Angelopoulos, Vassilis;

YEAR: 2014     DOI: 10.1002/2013JA019591

magnetosonic waves; ring current; THEMIS observation; wave excitation

2013

Analysis of EMIC-wave-moderated flux limitation of measured energetic ion spectra in multispecies magnetospheric plasmas

A differential Kennel-Petschek (KP) flux limit for magnetospheric energetic ions is devised taking into account multiple ion species effects on electromagnetic ion cyclotron (EMIC) waves that scatter the ions. The idea is that EMIC waves may limit the highest ion intensities during acceleration phases of storms and substorms (~ hour) while other mechanisms (e.g., charge exchange) may account for losses below those limits and over longer periods of time. This approach is applied to published Earth magnetosphere energetic ion ...

Mauk, B.;

YEAR: 2013     DOI: 10.1002/grl.50789

energetic ions; Radiation belts; ring current; Van Allen Probes



  1