Bibliography



Found 404 entries in the Bibliography.


Showing entries from 51 through 100


2019

Comparison of Van Allen Probes Energetic Electron Data with Corresponding GOES-15 Measurements: 2012-2018

Baker, D.N.; Zhao, H.; Li, X.; Kanekal, S.G.; Jaynes, A.N.; Kress, B.T.; Rodriguez, J.V.; Singer, H.J.; Claudepierre, S.G.; Fennell, J.F.; Hoxie, V.;

YEAR: 2019     DOI: 10.1029/2019JA027331

energetic particles; Magnetosphere:Inner; Magnetospheric configuration; Radiation belts; Space weather; Van Allen Probes

How Sudden, Intense Energetic Electron Enhancements Correlate With the Innermost Plasmapause Locations Under Various Solar Wind Drivers and Geomagnetic Conditions

In this report, the relationship between innermost plasmapause locations (Lpp) and initial electron enhancements during both storm and nonstorm (Dst > -30 nT) periods are examined using data from the Van Allen Probes. The geomagnetic storms are classified into coronal mass ejection (CME)-driven and corotating interaction region (CIR)-driven storms to explore their influences on the initial electron enhancements, respectively. We also study nonstorm time electron enhancements and observe frequent, sudden (within two consecuti ...

Khoo, L.-Y.; Li, X.; Zhao, H.; Chu, X.; Xiang, Z.; Zhang, K.;

YEAR: 2019     DOI: 10.1029/2019JA027412

energetic electron enhancements; Plasmapause; Radiation Belt Dynamics; Van Allen Probes

Remote Detection of Drift Resonance Between Energetic Electrons and Ultralow Frequency Waves: Multisatellite Coordinated Observation by Arase and Van Allen Probes

We report the electron flux modulations without corresponding magnetic fluctuations from unique multipoint satellite observations of the Arase (Exploration of Energization and Radiation in Geospace) and the Van Allen Probe (Radiation Belt Storm Probe [RBSP])-B satellites. On 30 March 2017, both Arase and RBSP-B observed periodic fluctuations in the relativistic electron flux with energies ranging from 500 keV to 2 MeV when they were located near the magnetic equator in the morning and dusk local time sectors, respectively. A ...

Teramoto, M.; Hori, T.; Saito, S.; Miyoshi, Y.; Kurita, S.; Higashio, N.; Matsuoka, A.; Kasahara, Y.; Kasaba, Y.; Takashima, T.; Nomura, R.; e, Nos\; Fujimoto, A.; Tanaka, Y.-M.; Shoji, M.; Tsugawa, Y.; Shinohara, M.; Shinohara, I.; Blake, J.; Fennell, J.F.; Claudepierre, S.G.; Turner, D.; Kletzing, C.; Sormakov, D.; Troshichev, O.;

YEAR: 2019     DOI: 10.1029/2019GL084379

Van Allen Probes

Remote Detection of Drift Resonance Between Energetic Electrons and Ultralow Frequency Waves: Multisatellite Coordinated Observation by Arase and Van Allen Probes

We report the electron flux modulations without corresponding magnetic fluctuations from unique multipoint satellite observations of the Arase (Exploration of Energization and Radiation in Geospace) and the Van Allen Probe (Radiation Belt Storm Probe [RBSP])-B satellites. On 30 March 2017, both Arase and RBSP-B observed periodic fluctuations in the relativistic electron flux with energies ranging from 500 keV to 2 MeV when they were located near the magnetic equator in the morning and dusk local time sectors, respectively. A ...

Teramoto, M.; Hori, T.; Saito, S.; Miyoshi, Y.; Kurita, S.; Higashio, N.; Matsuoka, A.; Kasahara, Y.; Kasaba, Y.; Takashima, T.; Nomura, R.; e, Nos\; Fujimoto, A.; Tanaka, Y.-M.; Shoji, M.; Tsugawa, Y.; Shinohara, M.; Shinohara, I.; Blake, J.; Fennell, J.F.; Claudepierre, S.G.; Turner, D.; Kletzing, C.; Sormakov, D.; Troshichev, O.;

YEAR: 2019     DOI: 10.1029/2019GL084379

Van Allen Probes

Cold Plasmaspheric Electrons Affected by ULF Waves in the Inner Magnetosphere: A Van Allen Probes Statistical Study

Six years of Van Allen Probes data are used to investigate cold plasmaspheric electrons affected by ultralow-frequency (ULF) waves in the inner magnetosphere (L<7) including spatial distributions, occurrence conditions, and resonant energy range. Events exhibit a global distribution within L= 4\textendash7 but preferentially occur at L\~5.5\textendash7 in the dayside, while there is higher occurrence rate in the duskside than dawnside. They can occur under different geomagnetic activities and solar wind velocities (VS), but ...

Ren, Jie; Zong, Q.; Zhou, X.; Spence, H.; Funsten, H.; Wygant, J.; Rankin, R.;

YEAR: 2019     DOI: 10.1029/2019JA027009

Cold plasmaspheric electrons; drift-bounce resonance; ULF waves; Van Allen Probes; Wave-particle interaction

Storm-time convection dynamics viewed from optical auroras

A series of statistical and event studies have demonstrated that the motion of patches in regions of Patchy Pulsating Aurora (PPA) is very close to, if not exactly, convection. Therefore, 2D maps of PPA motion provide us the opportunity to remotely sense magnetospheric convection with relatively high space and time resolution, subject to uncertainties associated with the mapping between the ionosphere and magnetosphere. In this study, we use THEMIS ASI (All Sky Imager) aurora observations combined with RBSP electric field an ...

Yang, Bing; Donovan, Eric; Liang, Jun; Ruohoniemi, Michael; McWilliams, Kathryn; Spanswick, Emma;

YEAR: 2019     DOI: 10.1016/j.jastp.2019.105088

Auroral streamer; convection; Fast earthward flows; pulsating aurora; Van Allen Probes

Variability of Quasilinear Diffusion Coefficients for Plasmaspheric Hiss

In the outer radiation belt, the acceleration and loss of high-energy electrons is largely controlled by wave-particle interactions. Quasilinear diffusion coefficients are an efficient way to capture the small-scale physics of wave-particle interactions due to magnetospheric wave modes such as plasmaspheric hiss. The strength of quasilinear diffusion coefficients as a function of energy and pitch angle depends on both wave parameters and plasma parameters such as ambient magnetic field strength, plasma number density, and co ...

Watt, C.; Allison, H.; Meredith, N.; Thompson, R.; Bentley, S.; Rae, I.; Glauert, S.; Horne, R.;

YEAR: 2019     DOI: 10.1029/2018JA026401

empirical; Magnetosphere; parameterization; stochastic; Van Allen Probes; wave-particle interactions

Variability of Quasilinear Diffusion Coefficients for Plasmaspheric Hiss

In the outer radiation belt, the acceleration and loss of high-energy electrons is largely controlled by wave-particle interactions. Quasilinear diffusion coefficients are an efficient way to capture the small-scale physics of wave-particle interactions due to magnetospheric wave modes such as plasmaspheric hiss. The strength of quasilinear diffusion coefficients as a function of energy and pitch angle depends on both wave parameters and plasma parameters such as ambient magnetic field strength, plasma number density, and co ...

Watt, C.; Allison, H.; Meredith, N.; Thompson, R.; Bentley, S.; Rae, I.; Glauert, S.; Horne, R.;

YEAR: 2019     DOI: 10.1029/2018JA026401

empirical; Magnetosphere; parameterization; stochastic; Van Allen Probes; wave-particle interactions

Global Occurrences of Auroral Kilometric Radiation Related to Suprathermal Electrons in Radiation Belts

Auroral kilometric radiation (AKR) can potentially produce serious damage to space-borne systems by accelerating trapped radiation belt electrons to relativistic energies. Here we examine the global occurrences of AKR emissions in radiation belts based on Van Allen Probes observations from 1 October 2012 to 31 December 2016. The statistical results (1,848 events in total) show that AKR covers a broad region of L= 3\textendash6.5 and 00\textendash24 magnetic local time (MLT), with a higher occurrence on the nightside (20\text ...

Zhao, Wanli; Liu, Si; Zhang, Sai; Zhou, Qinghua; Yang, Chang; He, Yihua; Gao, Zhonglei; Xiao, Fuliang;

YEAR: 2019     DOI: 10.1029/2019GL083944

Auroral kilometric radiation; global occurrence; Radiation belt; suprathermal electron flux enhancenments; Van Allen Probes

Lightning Contribution to Overall Whistler Mode Wave Intensities in the Plasmasphere

Electromagnetic waves generated by lightning propagate into the plasmasphere as dispersed whistlers. They can therefore influence the overall wave intensity in space, which, in turn, is important for dynamics of the Van Allen radiation belts. We analyze spacecraft measurements in low-Earth orbit as well as in high-altitude equatorial region, together with a ground-based estimate of lightning activity. We accumulate wave intensities when the spacecraft are magnetically connected to thunderstorms and compare them with measurem ...

ahlava, J.; emec, F.; Santolik, O.; a, Kolma\v; Hospodarsky, G.; Parrot, M.; Kurth, W.; Kletzing, C.;

YEAR: 2019     DOI: 10.1029/2019GL083918

DEMETER; Lightning; Van Allen Probes; whistler mode; WWLLN

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

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

Nonlinear Electron Interaction With Intense Chorus Waves: Statistics of Occurrence Rates

A comprehensive statistical analysis on 8 years of lower-band chorus wave packets measured by the Van Allen Probes and THEMIS spacecraft is performed to examine whether, when, and where these waves are above the theoretical threshold for nonlinear resonant wave-particle interaction. We find that \~5\textendash30\% of all chorus waves interact nonlinearly with \~30- to 300-keV electrons possessing equatorial pitch angles of >40\textdegree in the outer radiation belt, especially during disturbed (AE>500 nT) periods with energe ...

Zhang, X.-J.; Mourenas, D.; Artemyev, A.; Angelopoulos, V.; Bortnik, J.; Thorne, R.; Kurth, W.; Kletzing, C.; Hospodarsky, G.;

YEAR: 2019     DOI: 10.1029/2019GL083833

chorus waves; Electron acceleration; nonlinear wave particle interaction; THEMIS; Van Allen Probes; wave packet size

Nonlinear Electron Interaction With Intense Chorus Waves: Statistics of Occurrence Rates

A comprehensive statistical analysis on 8 years of lower-band chorus wave packets measured by the Van Allen Probes and THEMIS spacecraft is performed to examine whether, when, and where these waves are above the theoretical threshold for nonlinear resonant wave-particle interaction. We find that \~5\textendash30\% of all chorus waves interact nonlinearly with \~30- to 300-keV electrons possessing equatorial pitch angles of >40\textdegree in the outer radiation belt, especially during disturbed (AE>500 nT) periods with energe ...

Zhang, X.-J.; Mourenas, D.; Artemyev, A.; Angelopoulos, V.; Bortnik, J.; Thorne, R.; Kurth, W.; Kletzing, C.; Hospodarsky, G.;

YEAR: 2019     DOI: 10.1029/2019GL083833

chorus waves; Electron acceleration; nonlinear wave particle interaction; THEMIS; Van Allen Probes; wave packet size

Generation of EMIC Waves and Effects on Particle Precipitation During a Solar Wind Pressure Intensification with B z >

During geomagnetic storms, some fraction of the solar wind energy is coupled via reconnection at the dayside magnetopause, a process that requires a southward interplanetary magnetic field Bz. Through a complex sequence of events, some of this energy ultimately drives the generation of electromagnetic ion cyclotron (EMIC) waves, which can then scatter energetic electrons and ions from the radiation belts. In the event described in this paper, the interplanetary magnetic field remained northward throughout the event, a condit ...

Lessard, Marc; Paulson, Kristoff; Spence, Harlan; Weaver, Carol; Engebretson, Mark; Millan, Robyn; Woodger, Leslie; Halford, Alexa; Horne, Richard; Rodger, Craig; Hendry, Aaron;

YEAR: 2019     DOI: 10.1029/2019JA026477

Van Allen Probes

Timescales for electron quasi-linear diffusion by lower-band chorus waves: the effects of ω pe / Ω ce dependence on geomagnetic activity

Electron scattering by chorus waves is an important mechanism that can lead to fast electron acceleration and loss in the outer radiation belt. Making use of Van Allen Probes measurements, we present the first statistical survey of megaelectron volt electron pitch angle and energy quasi-linear diffusion rates by chorus waves as a function of L-shell, local time, and AE index, taking into account the local electron plasma frequency to gyrofrequency ratio ωpe/Ωce, chorus wave frequency, and resonance wave amplitude. We demon ...

Agapitov, O.; Mourenas, D.; Artemyev, A.; Hospodarsky, G.; Bonnell, J.W.;

YEAR: 2019     DOI: 10.1029/2019GL083446

magnetosphere plasma density; quasi-linear scattering and acceleration; Van Allen Probes; wave-particle interactions

EMIC waves converted from equatorial noise due to M/Q=2 ions in the plasmasphere: Observations from Van Allen Probes and Arase

Equatorial noise (EN) emissions are observed inside and outside the plasmapause. EN emissions are referred to as magnetosonic mode waves. Using data from Van Allen Probes and Arase, we found conversion from EN emissions to electromagnetic ion cyclotron (EMIC) waves in the plasmasphere and in the topside ionosphere. A low frequency part of EN emissions becomes EMIC waves through branch splitting of EN emissions, and the mode conversion from EN to EMIC waves occurs around the frequency of M/Q=2 (deuteron and/or alpha particles ...

Miyoshi, Y.; Matsuda, S.; Kurita, S.; Nomura, K.; Keika, K.; Shoji, M.; Kitamura, N.; Kasahara, Y.; Matsuoka, A.; Shinohara, I.; Shiokawa, K.; Machida, S.; Santolik, O.; Boardsen, S.A.; Horne, R.B.; Wygant, J.F.;

YEAR: 2019     DOI: 10.1029/2019GL083024

Arase; EMIC; M/Q=2 ions; Magnetsonic waves; plasmasphere; Van Allen Probes

EMIC waves converted from equatorial noise due to M/Q=2 ions in the plasmasphere: Observations from Van Allen Probes and Arase

Equatorial noise (EN) emissions are observed inside and outside the plasmapause. EN emissions are referred to as magnetosonic mode waves. Using data from Van Allen Probes and Arase, we found conversion from EN emissions to electromagnetic ion cyclotron (EMIC) waves in the plasmasphere and in the topside ionosphere. A low frequency part of EN emissions becomes EMIC waves through branch splitting of EN emissions, and the mode conversion from EN to EMIC waves occurs around the frequency of M/Q=2 (deuteron and/or alpha particles ...

Miyoshi, Y.; Matsuda, S.; Kurita, S.; Nomura, K.; Keika, K.; Shoji, M.; Kitamura, N.; Kasahara, Y.; Matsuoka, A.; Shinohara, I.; Shiokawa, K.; Machida, S.; Santolik, O.; Boardsen, S.A.; Horne, R.B.; Wygant, J.F.;

YEAR: 2019     DOI: 10.1029/2019GL083024

Arase; EMIC; M/Q=2 ions; Magnetsonic waves; plasmasphere; Van Allen Probes

Global occurrences of electrostatic electron cyclotron harmonic waves associated with radiation belt electron distributions

Electrostatic electron cyclotron harmonic (ECH) waves can yield diffuse aurora primarily at higher L-shells by driving efficient precipitation loss of plasma sheet electrons. Here using the Van Allen Probes high resolution data, we examine in detail the global occurrences of ECH waves during the period from October 1, 2012 to June 30, 2017 and find that there are totally 419 events of enhanced ECH waves. The statistical results demonstrate that ECH waves can be present over a broad region of L=4-6 and 00-24 MLT, with a highe ...

Chen, Yaru; Zhou, Qinghua; He, Yihua; Yang, Chang; Liu, Si; Gao, Zhonglei; Xiao, Fuliang;

YEAR: 2019     DOI: 10.1029/2019GL082668

electron ring distribution; global occurrences; Radiation belt; Van Allen Probe observation; Van Allen Probes; waves

Energetic Electron Precipitation: Multievent Analysis of Its Spatial Extent During EMIC Wave Activity

Electromagnetic ion cyclotron (EMIC) waves can drive precipitation of tens of keV protons and relativistic electrons, and are a potential candidate for causing radiation belt flux dropouts. In this study, we quantitatively analyze three cases of EMIC-driven precipitation, which occurred near the dusk sector observed by multiple Low-Earth-Orbiting (LEO) Polar Operational Environmental Satellites/Meteorological Operational satellite programme (POES/MetOp) satellites. During EMIC wave activity, the proton precipitation occurred ...

Capannolo, L.; Li, W.; Ma, Q.; Shen, X.-C.; Zhang, X.-J.; Redmon, R.; Rodriguez, J.; Engebretson, M.; Kletzing, C.; Kurth, W.; Hospodarsky, G.; Spence, H.; Reeves, G.; Raita, T.;

YEAR: 2019     DOI: 10.1029/2018JA026291

EMIC waves; energetic electron precipitation; pitch angle scattering; quasi-linear theory; radiation belts dropouts; Van Allen Probes

Multiyear Measurements of Radiation Belt Electrons: Acceleration, Transport, and Loss

In addition to clarifying morphological structures of the Earth\textquoterights radiation belts, it has also been a major achievement of the Van Allen Probes mission to understand more thoroughly how highly relativistic and ultrarelativistic electrons are accelerated deep inside the radiation belts. Prior studies have demonstrated that electrons up to energies of 10 megaelectron volts (MeV) can be produced over broad regions of the outer Van Allen zone on timescales of minutes to a few hours. It often is seen that geomagneti ...

Baker, Daniel; Hoxie, Vaughn; Zhao, Hong; Jaynes, Allison; Kanekal, Shri; Li, Xinlin; Elkington, Scot;

YEAR: 2019     DOI: 10.1029/2018JA026259

convection electric field; Energetic particle deep penetration; Low L Region; Radiation belts; Van Allen Probes

Multi-instrument Observations of Mesoscale Enhancement of Subauroral Polarization Stream Associated With an Injection

Subauroral polarization streams (SAPS) prefer geomagnetically disturbed conditions and strongly correlate with geomagnetic indexes. However, the temporal evolution of SAPS and its relationship with dynamic and structured ring current and particle injection are still not well understood. In this study, we performed detailed analysis of temporal evolution of SAPS during a moderate storm on 18 May 2013 using conjugate observations of SAPS from the Van Allen Probes (VAP) and the Super Dual Auroral Radar Network (SuperDARN). The ...

Wang, Zihan; Zou, Shasha; Shepherd, Simon; Liang, Jun; Gjerloev, Jesper; Ruohoniemi, Michael; Kunduri, Bharat; Wygant, John;

YEAR: 2019     DOI: 10.1029/2019JA026535

Field-Aligned Current; Particle Injection; Sub-auroral Polarization Stream; Van Allen Probes

Quantification of Energetic Electron Precipitation Driven by Plume Whistler Mode Waves, Plasmaspheric Hiss, and Exohiss

Whistler mode waves are important for precipitating energetic electrons into Earth\textquoterights upper atmosphere, while the quantitative effect of each type of whistler mode wave on electron precipitation is not well understood. In this letter, we evaluate energetic electron precipitation driven by three types of whistler mode waves: plume whistler mode waves, plasmaspheric hiss, and exohiss observed outside the plasmapause. By quantitatively analyzing three conjunction events between Van Allen Probes and POES/MetOp satel ...

Li, W.; Shen, X.-C.; Ma, Q.; Capannolo, L.; Shi, R.; Redmon, R.; Rodriguez, J.; Reeves, G.; Kletzing, C.; Kurth, W.; Hospodarsky, G.;

YEAR: 2019     DOI: 10.1029/2019GL082095

electron precipitation; hiss; plasmaspheric plume; Plume wave; Van Allen Probes; whistler mode wave

The dynamics of Van Allen belts revisited

Shprits, Yuri; Horne, Richard; Kellerman, Adam; Drozdov, Alexander;

YEAR: 2019     DOI: 10.1038/nphys4350

Van Allen Probes

Reply to \textquoterightThe dynamics of Van Allen belts revisited\textquoteright

Mann, I.; Ozeke, L.; Morley, S.; Murphy, K.; Claudepierre, S.; Turner, D.; Baker, D.; Rae, I.; Kale, A.; Milling, D.; Boyd, A.; Spence, H.; Singer, H.; Dimitrakoudis, S.; Daglis, I.; Honary, F.;

YEAR: 2019     DOI: 10.1038/nphys4351

Van Allen Probes

Van Allen Probes observations of chorus wave vector orientations: Implications for the chorus-to-hiss mechanism

Using observations from the Van Allen Probes EMFISIS instrument, coupled with ray tracing simulations, we determine the fraction of chorus wave power with the conditions required to access the plasmasphere and evolve into plasmaspheric hiss. It is found that only an extremely small fraction of chorus occurs with the required wave vector orientation, carrying only a small fraction of the total chorus wave power. The exception is on the edge of plasmaspheric plumes, where strong azimuthal density gradients are present. In thes ...

Hartley, D.; Kletzing, C.; Chen, L.; Horne, R.; ik, O.;

YEAR: 2019     DOI: 10.1029/2019GL082111

chorus waves; EMFISIS; Plasmaspheric Hiss; plasmaspheric plumes; Van Allen Probes; wave normal angle

Global Empirical Picture of Magnetospheric Substorms Inferred From Multimission Magnetometer Data

Magnetospheric substorms represent key explosive processes in the interaction of the Earth\textquoterights magnetosphere with the solar wind, and their understanding and modeling are critical for space weather forecasting. During substorms, the magnetic field on the nightside is first stretched in the antisunward direction and then it rapidly contracts earthward bringing hot plasmas from the distant space regions into the inner magnetosphere, where they contribute to geomagnetic storms and Joule dissipation in the polar iono ...

Stephens, G.; Sitnov, M.; Korth, H.; Tsyganenko, N.; Ohtani, S.; Gkioulidou, M.; . Y. Ukhorskiy, A;

YEAR: 2019     DOI: 10.1029/2018JA025843

Current sheet thinning; Data-mining; Magnetotail dipolarization; Storm-substorm relationship; substorm current wedge; substorms; Van Allen Probes

Low-Energy (+ Ion Outflow Directly Into the Inner Magnetosphere: Van Allen Probes Observations

The heavy ion component of the low-energy (eV to hundreds of eV) ion population in the inner magnetosphere, also known as the O+ torus, is a crucial population for various aspects of magnetospheric dynamics. Yet even though its existence has been known since the 1980s, its formation remains an open question. We present a comprehensive study of a low-energy (

Gkioulidou, Matina; Ohtani, S.; . Y. Ukhorskiy, A; Mitchell, D.; Takahashi, K.; Spence, H.; Wygant, J.; Kletzing, C.; Barnes, R.;

YEAR: 2019     DOI: 10.1029/2018JA025862

inner magnetosphere; O+ outflow; Van Allen Probes

Properties of Whistler Mode Waves in Earth\textquoterights Plasmasphere and Plumes

Whistler mode wave properties inside the plasmasphere and plumes are systematically investigated using 5-year data from Van Allen Probes. The occurrence and intensity of whistler mode waves in the plasmasphere and plumes exhibit dependences on magnetic local time, L, and AE. Based on the dependence of the wave normal angle and Poynting flux direction on L shell and normalized wave frequency to electron cyclotron frequency (fce), whistler mode waves are categorized into four types. Type I: ~0.5 fce with oblique wave normal an ...

Shi, Run; Li, Wen; Ma, Qianli; Green, Alex; Kletzing, Craig; Kurth, William; Hospodarsky, George; Claudepierre, Seth; Spence, Harlan; Reeves, Geoff;

YEAR: 2019     DOI: 10.1029/2018JA026041

Plasmaspheric Hiss; plasmaspheric plume; Van Allen Probes; whistler mode waves

2018

Observations and Fokker-Planck simulations of the L-shell, energy, and pitch-angle structure of Earth\textquoterights electron radiation belts during quiet times

The evolution of the radiation belts in L-shell (L), energy (E), and equatorial pitch-angle (α0) is analyzed during the calm 11-day interval (March 4 \textendashMarch 15) following the March 1 storm 2013. Magnetic Electron and Ion Spectrometer (MagEIS) observations from Van Allen Probes are interpreted alongside 1D and 3D Fokker-Planck simulations combined with consistent event-driven scattering modeling from whistler mode hiss waves. Three (L, E, α0)-regions persist through 11 days of hiss wave scattering; the pitch-angle ...

Ripoll, -F.; Loridan, V.; Denton, M.; Cunningham, G.; Reeves, G.; ik, O.; Fennell, J.; Turner, D.; . Y. Drozdov, A; Villa, J.; . Y. Shprits, Y; Thaller, S.; Kurth, W.; Kletzing, C.; Henderson, M.; . Y. Ukhorskiy, A;

YEAR: 2018     DOI: 10.1029/2018JA026111

electron lifetime; hiss waves; pitch-angle diffusion coefficient; Radiation belts; Van Allen Probes; wave particle interactions

Determination of the Equatorial Electron Differential Flux From Observations at Low Earth Orbit

Variations in the high-energy relativistic electron flux of the radiation belts depend on transport, acceleration, and loss processes, and importantly on the lower-energy seed population. However, data on the seed population is limited to a few satellite missions. Here we present a new method that utilizes data from the Medium Energy Proton/Electron Detector on board the low-altitude Polar Operational Environmental Satellites to retrieve the seed population at a pitch angle of 90\textdegree. The integral flux values measured ...

Allison, Hayley; Horne, Richard; Glauert, Sarah; Del Zanna, Giulio;

YEAR: 2018     DOI: 10.1029/2018JA025786

electrons; integral flux; Radiation belts; seed population; Van Allen Probes

On the Initial Enhancement of Energetic Electrons and the Innermost Plasmapause Locations: CME-Driven Storm Periods

Using Van Allen Probes\textquoteright observations and established plasmapause location (Lpp) models, we investigate the relationship between the location of the initial enhancement (IE) of energetic electrons and the innermost (among all magnetic local time sectors) Lpp over five intense storm periods. Our study reveals that the IE events for 30 keV to 2MeV electrons always occurred outside of the innermost Lpp. On average, the inner extent of the IE events (LIE) for <800 keV electrons was closer to the innermost Lpp when c ...

Khoo, Leng; Li, Xinlin; Zhao, Hong; Sarris, Theodore; Xiang, Zheng; Zhang, Kun; Kellerman, Adam; Blake, Bernard;

YEAR: 2018     DOI: 10.1029/2018JA026074

energetic electron; enhancements; plasmasphere; Radiation belt; Van Allen Probes

Longitudinal Structure of Oxygen Torus in the Inner Magnetosphere: Simultaneous Observations by Arase and Van Allen Probe A

Simultaneous observations of the magnetic field and plasma waves made by the Arase and Van Allen Probe A satellites at different magnetic local time (MLT) enable us to deduce the longitudinal structure of an oxygen torus for the first time. During 04:00\textendash07:10 UT on 24 April 2017, Arase flew from L = 6.2 to 2.0 in the morning sector and detected an enhancement of the average plasma mass up to ~3.5 amu around L = 4.9\textendash5.2 and MLT = 5.0 hr, implying that the plasma consists of approximately 15\% O+ ions. Prob ...

e, M.; Matsuoka, A.; Kumamoto, A.; Kasahara, Y.; Goldstein, J.; Teramoto, M.; Tsuchiya, F.; Matsuda, S.; Shoji, M.; Imajo, S.; Oimatsu, S.; Yamamoto, K.; Obana, Y.; Nomura, R.; Fujimoto, A.; Shinohara, I.; Miyoshi, Y.; Kurth, W.; Kletzing, C.; Smith, C.; MacDowall, R.;

YEAR: 2018     DOI: 10.1029/2018GL080122

Arase satellite; Geomagnetic storm; inner magnetosphere; oxygen torus; simultaneous observation; Van Allen Probes; Van Allen Probes satellite

Quasiperiodic Whistler Mode Emissions Observed by the Van Allen Probes Spacecraft

Quasiperiodic (QP) emissions are whistler mode electromagnetic waves observed in the inner magnetosphere which exhibit a QP time modulation of the wave intensity. We analyze 768 QP events observed during the first five years of the operation of the Van Allen Probes spacecraft (09/2012\textendash10/2017). Multicomponent wave measurements performed in the equatorial region, where the emissions are likely generated, are used to reveal new experimental information about their properties. We show that the events are observed near ...

emec, F.; Hospodarsky, G.; a, B.; Demekhov, A.; Pasmanik, D.; ik, O.; Kurth, W.; Hartley, D.;

YEAR: 2018     DOI: 10.1029/2018JA026058

EMFISIS; QP emissions; quasiperiodic; Van Allen Probes

Quasiperiodic Whistler Mode Emissions Observed by the Van Allen Probes Spacecraft

Quasiperiodic (QP) emissions are whistler mode electromagnetic waves observed in the inner magnetosphere which exhibit a QP time modulation of the wave intensity. We analyze 768 QP events observed during the first five years of the operation of the Van Allen Probes spacecraft (09/2012\textendash10/2017). Multicomponent wave measurements performed in the equatorial region, where the emissions are likely generated, are used to reveal new experimental information about their properties. We show that the events are observed near ...

emec, F.; Hospodarsky, G.; a, B.; Demekhov, A.; Pasmanik, D.; ik, O.; Kurth, W.; Hartley, D.;

YEAR: 2018     DOI: 10.1029/2018JA026058

EMFISIS; QP emissions; quasiperiodic; Van Allen Probes

Evolution of electron distribution driven by nonlinear resonances with intense field-aligned chorus waves

Resonant electron interaction with whistler-mode chorus waves is recognized as one of the main drivers of radiation belt dynamics. For moderate wave intensity, this interaction is well described by quasi-linear theory. However, recent statistics of parallel propagating chorus waves have demonstrated that 5 - 20\% of the observed waves are sufficiently intense to interact nonlinearly with electrons. Such interactions include phase trapping and phase bunching (nonlinear scattering) effects not described by quasi-linear diffusi ...

Vainchtein, D.; Zhang, X.-J.; Artemyev, A.; Mourenas, D.; Angelopoulos, V.; Thorne, R.;

YEAR: 2018     DOI: 10.1029/2018JA025654

Van Allen Probes

Generation of lower L -shell dayside chorus by energetic electrons from the plasmasheet

Currently, the generation mechanism for the lower L-shell dayside chorus has still remained an open question. Here, we report two storm events: 06-07 March 2016 and 20-21 January 2016, when Van Allen Probes observed enhanced dayside chorus with lower and higher wave normal angles (the angles between the wave vector and the geomagnetic field) in the region of L = 3.5-6.3 and MLT = 5.6-13.5. Hot and energetic (\~ 1-100 keV) electrons displayed enhancements in fluxes and anisotropy when they were injected from the plasmasheet a ...

He, Yihua; Xiao, Fuliang; Su, Zhenpeng; Zheng, Huinan; Yang, Chang; Liu, Si; Zhou, Qinghua;

YEAR: 2018     DOI: 10.1029/2017JA024889

Dayside chorus generation; Radiation belt; Van Allen Probes; Wave-particle interaction

Variation in Plasmaspheric Hiss Wave Power With Plasma Density

Plasmaspheric hiss waves are commonly observed in the inner magnetosphere. These waves efficiently scatter electrons, facilitating their precipitation into the atmosphere. Predictive inner magnetosphere simulations often model hiss waves using parameterized empirical maps of observed hiss power. These maps nearly always include parameterization by magnetic L value. In this work, data from the Van Allen Probes are used to compare variation in hiss wave power with variation in both L value and cold plasma density. It is found ...

Malaspina, David; Ripoll, Jean-Francois; Chu, Xiangning; Hospodarsky, George; Wygant, John;

YEAR: 2018     DOI: 10.1029/2018GL078564

inner magnetosphere; Plasmaspheric Hiss; Radiation belts; Van Allen Probes; Wave models

Nonlinear drift resonance between charged particles and ultra-low frequency waves: Theory and Observations

In Earth\textquoterights inner magnetosphere, electromagnetic waves in the ultra-low frequency (ULF) range play an important role in accelerating and diffusing charged particles via drift resonance. In conventional drift-resonance theory, linearization is applied under the assumption of weak wave-particle energy exchange so particle trajectories are unperturbed. For ULF waves with larger amplitudes and/or durations, however, the conventional theory becomes inaccurate since particle trajectories are strongly perturbed. Here, ...

Li, Li; Zhou, Xu-Zhi; Omura, Yoshiharu; Wang, Zi-Han; Zong, Qiu-Gang; Liu, Ying; Hao, Yi-Xin; Fu, Sui-Yan; Kivelson, Margaret; Rankin, Robert; Claudepierre, Seth; Wygant, John;

YEAR: 2018     DOI: 10.1029/2018GL079038

drift resonance; nonlinear process; Particle acceleration; Radiation belts; ULF waves; Van Allen Probes; wave-particle interactions

Test of Ion Cyclotron Resonance Instability Using Proton Distributions Obtained From Van Allen Probe-A Observations

Anisotropic velocity distributions of protons have long been considered as free energy sources for exciting electromagnetic ion cyclotron (EMIC) waves in the Earth\textquoterights magnetosphere. Here we rigorously calculated the proton anisotropy parameter using proton data obtained from Van Allen Probe-A observations. The calculations are performed for times during EMIC wave events (distinguishing the times immediately after and before EMIC wave onsets) and for times exhibiting no EMIC waves. We find that the anisotropy val ...

Noh, Sung-Jun; Lee, Dae-Young; Choi, Cheong-Rim; Kim, Hyomin; Skoug, Ruth;

YEAR: 2018     DOI: 10.1029/2018JA025385

EMIC waves; Ion cyclotron instability; RBSP; temperature anisotropy; Van Allen Probes

The composition of plasma inside geostationary orbit based on Van Allen Probes observations

The composition of the inner magnetosphere is of great importance for determining the plasma pressure, and thus the currents and magnetic field configuration. In this study, we perform a statistical survey of equatorial plasma pressure distributions and investigate the relative contributions of ions and electron with different energies inside of geostationary orbit under two AE levels based on over sixty months of observations from the HOPE and RBSPICE mass spectrometers on board Van Allen Probes. We find that the total and ...

Yue, Chao; Bortnik, Jacob; Li, Wen; Ma, Qianli; Gkioulidou, Matina; Reeves, Geoffrey; Wang, Chih-Ping; Thorne, Richard; T. Y. Lui, Anthony; Gerrard, Andrew; Spence, Harlan; Mitchell, Donald;

YEAR: 2018     DOI: 10.1029/2018JA025344

ion composition; plasma pressure; Plasmapause; Van Allen Probes

Determining the wave vector direction of equatorial fast magnetosonic waves

We perform polarization analysis of the equatorial fast magnetosonic waves electric field over a 20 minute interval of Van Allen Probes A Waveform Receiver burst mode data. The wave power peaks at harmonics of the proton cyclotron frequency indicating the spacecraft is near or in the source region. The wave vector is inferred from the direction of the major axis of the electric field polarization ellipsoid and the sign of the phase between the longitudinal electric and compressional magnetic field components. We show that wa ...

Boardsen, Scott; Hospodarsky, George; Min, Kyungguk; Averkamp, Terrance; Bounds, Scott; Kletzing, Craig; Pfaff, Robert;

YEAR: 2018     DOI: 10.1029/2018GL078695

equatorial fast magnetosonic; E-field polarization analysis; Poynting Flux analysis; Van Allen Probes; wave vector analysis

EMIC wave events during the four GEM QARBM challenge intervals

This paper presents observations of EMIC waves from multiple data sources during the four GEM challenge events in 2013 selected by the GEM \textquotedblleftQuantitative Assessment of Radiation Belt Modeling\textquotedblright focus group: March 17-18 (Stormtime Enhancement), May 31-June 2 (Stormtime Dropout), September 19-20 (Non-storm Enhancement), and September 23-25 (Non-storm Dropout). Observations include EMIC wave data from the Van Allen Probes, GOES, and THEMIS spacecraft in the near-equatorial magnetosphere and from s ...

Engebretson, M.; Posch, J.; Braun, D.; Li, W.; Ma, Q.; Kellerman, A.; Huang, C.-L.; Kanekal, S.; Kletzing, C.; Wygant, J.; Spence, H.; Baker, D.; Fennell, J.; Angelopoulos, V.; Singer, H.; Lessard, M.; Horne, R.; Raita, T.; Shiokawa, K.; Rakhmatulin, R.; Dmitriev, E.; Ermakova, E.;

YEAR: 2018     DOI: 10.1029/2018JA025505

Van Allen Probes

Impulsively Excited Nightside Ultralow Frequency Waves Simultaneously Observed On and Off the Magnetic Equator

The Arase spacecraft is capable of observing ultralow-frequency waves in the inner magnetosphere at intermediate magnetic latitudes, a region sparsely covered by previous space craft missions. We report a series of impulsively excited fundamental toroidal mode standing Alfv\ en waves in the midnight sector observed by Arase outside the plasmasphere at magnetic latitudes 13\textendash24\textdegree . The wave onsets are concurrent with Pi2 onsets detected by the Van Allen Probe B spacecraft at the magnetic equator in the dusks ...

Takahashi, Kazue; Denton, Richard; Motoba, Tetsuo; Matsuoka, Ayako; Kasaba, Yasumasa; Kasahara, Yoshiya; Teramoto, Mariko; Shoji, Masafumi; Takahashi, Naoko; Miyoshi, Yoshizumi; e, Masahito; Kumamoto, Atsushi; Tsuchiya, Fuminori; Redmon, Robert; Rodriguez, Juan;

YEAR: 2018     DOI: 10.1029/2018GL078731

Van Allen Probes

Longitudinal dependence of whistler mode electromagnetic waves in the Earth\textquoterights inner magnetosphere

We use the measurements performed by the DEMETER (2004-2010) and the Van Allen Probes (2012-2016, still operating) spacecraft to investigate the longitudinal dependence of the intensity of whistler mode waves in the Earth\textquoterights inner magnetosphere. We show that a significant longitudinal dependence is observed inside the plasmasphere on the nightside, primarily in the frequency range 400 Hz\textendash2 kHz. On the other hand, almost no longitudinal dependence is observed on the dayside. The obtained results are com ...

ahlava, J.; emec, F.; ik, O.; a, I.; Hospodarskyy, G.; Parrot, M.; Kurth, W.; Bortnik, J.; Kletzing, C.;

YEAR: 2018     DOI: 10.1029/2018JA025284

DEMETER; Van Allen Probes; Whistler waves

Understanding the Driver of Energetic Electron Precipitation Using Coordinated Multisatellite Measurements

Magnetospheric plasma waves play a significant role in ring current and radiation belt dynamics, leading to pitch angle scattering loss and/or stochastic acceleration of the particles. During a non-storm time dropout event on 24 September 2013, intense electromagnetic ion cyclotron (EMIC) waves were detected by Van Allen Probe A (Radiation Belt Storm Probes-A). We quantitatively analyze a conjunction event when Van Allen Probe A was located approximately along the same magnetic field line as MetOp-01, which detected simultan ...

Capannolo, L.; Li, W.; Ma, Q.; Zhang, X.-J.; Redmon, R.; Rodriguez, J.; Kletzing, C.; Kurth, W.; Hospodarsky, G.; Engebretson, M.; Spence, H.; Reeves, G.;

YEAR: 2018     DOI: 10.1029/2018GL078604

EMIC waves; energetic particle precipitation; pitch angle scattering; Radiation belts; Van Allen Probes; wave particle interactions

Electron flux enhancements at L = 4.2 observed by Global Positioning System satellites: Relationship with solar wind and geomagnetic activity

Determining solar wind and geomagnetic activity parameters most favorable to strong electron flux enhancements is an important step towards forecasting radiation belt dynamics. Using electron flux measurements from Global Positioning System satellites at L = 4.2 in 2009-2016, we seek statistical relationships between flux enhancements at different energies and solar wind dynamic pressure Pdyn, AE, and Kp, from hundreds of events inside and outside the plasmasphere. Most ⩾1 MeV electron flux enhancements occur during non-st ...

Zhang, X.-J.; Mourenas, D.; Artemyev, A.; Angelopoulos, V.; Thorne, R.;

YEAR: 2018     DOI: 10.1029/2018JA025497

chorus waves; Electron energization; Electron flux enhancements; GPS satellites; Radiation belt; Solar wind and geomagnetic activities; Van Allen Probes

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

Modeling the Depletion and Recovery of the Outer Radiation Belt During a Geomagnetic Storm: Combined MHD and Test Particle Simulations

During geomagnetic storms the intensities of the outer radiation belt electron population can exhibit dramatic variability. Deep depletions in intensity during the main phase are followed by increases during the recovery phase, often to levels that significantly exceed their pre-storm values. To study these processes, we simulate the evolution of the outer radiation belt during the 17 March 2013 geomagnetic storm using our newly-developed radiation belt model (CHIMP) based on test particle and coupled 3D ring current and glo ...

Sorathia, K.; . Y. Ukhorskiy, A; Merkin, V.; Fennell, J.; Claudepierre, S.;

YEAR: 2018     DOI: 10.1029/2018JA025506

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

Observed propagation route of VLF transmitter signals in the magnetosphere

Signals of powerful ground transmitters at various places have been detected by satellites in near-Earth space. The study on propagation mode, ducted or nonducted, has attracted much attentions for several decades. Based on the statistical results from Van Allen Probes (data from Oct. 2012 to Mar. 2017) and DEMETER satellite (from Jan. 2006 to Dec. 2007), we present the ground transmitter signals distributed clearly in ionosphere and magnetosphere. The observed propagation route in the meridian plane in the magnetosphere for ...

Zhang, Zhenxia; Chen, Lunjin; Li, Xinqiao; Xia, Zhiyang; Heelis, Roderick; Horne, Richard;

YEAR: 2018     DOI: 10.1029/2018JA025637

ducted propagation; in magnetosphere; nonducted propagation; Van Allen Probes; VLF transmitter



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