Found 331 entries in the Bibliography.
Showing entries from 1 through 50
| 2020 |
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Bayesian Inference of Quasi-Linear Radial Diffusion Parameters using Van Allen Probes Abstract The Van Allen radiation belts in the magnetosphere have been extensively studied using models based on radial diffusion theory, which is derived from a quasi-linear approach with prescribed inner and outer boundary conditions. The 1D diffusion model requires the knowledge of a diffusion coefficient and an electron loss timescale, which is typically parameterized in terms of various quantities such as the spatial (L) coordinate or a geomagnetic index (e.g., Kp). These terms are typically empirically derived, not dire ... Sarma, Rakesh; Chandorkar, Mandar; Zhelavskaya, Irina; Shprits, Yuri; Drozdov, Alexander; Camporeale, Enrico; YEAR: 2020 DOI: 10.1029/2019JA027618 radial diffusion; Magnetosphere; Bayesian inference; Van Allen radiation belt; Van Allen Probes |
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The Relation Between Electron Cyclotron Harmonic Waves and Plasmapause: Case and Statistical Studies Abstract Observationally, electron cyclotron harmonic (ECH) waves are often terminated at the outer boundary of the plasmasphere boundary layer (PBL, i.e., plasmapause). Physics of this empirical relation is not well established. In this study, two categories of ECH waves are shown by their different behaviors near PBL. For Category I, all bands of ECH waves terminate at PBL because the density ratio (nh/nc) between hot and cold electrons decreases dramatically across PBL. For Category II, ECH waves, especially the lower har ... Liu, Xu; Chen, Lunjin; Xia, Zhiyang; YEAR: 2020 DOI: 10.1029/2020GL087365 two types of ECH wave; Plasmapause; instability; excitation and attenuation mechanism; statistical characteristics of two types of ECH wave; Van Allen Probes |
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The Effect of Plasma Boundaries on the Dynamic Evolution of Relativistic Radiation Belt Electrons Abstract Understanding the dynamic evolution of relativistic electrons in the Earth s radiation belts during both storm and nonstorm times is a challenging task. The U.S. National Science Foundation s Geospace Environment Modeling (GEM) focus group “Quantitative Assessment of Radiation Belt Modeling” has selected two storm time and two nonstorm time events that occurred during the second year of the Van Allen Probes mission for in-depth study. Here, we perform simulations for these GEM challenge events using the 3D Versa ... Wang, Dedong; Shprits, Yuri; Zhelavskaya, Irina; Effenberger, Frederic; Castillo, Angelica; Drozdov, Alexander; Aseev, Nikita; Cervantes, Sebastian; YEAR: 2020 DOI: 10.1029/2019JA027422 Radiation belt; simulation; relativistic electrons; magnetopause shadowing; Wave-particle interaction; Plasmapause; Van Allen Probes |
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Abstract We study quasiperiodic very low frequency (VLF) emissions observed simultaneously by Van Allen Probes spacecraft and Kannuslehto and Lovozero ground-based stations on 25 December 2015. Both Van Allen Probes A and B detected quasiperiodic emissions, probably originated from a common source, and observed on the ground. In order to locate possible regions of wave generation, we analyze wave-normal angles with respect to the geomagnetic field, Poynting flux direction, and cyclotron instability growth rate calculated by ... Demekhov, A.; Titova, E.; Maninnen, J.; Pasmanik, D.; Lubchich, A.; Santolik, O.; Larchenko, A.; Nikitenko, A.; Turunen, T.; YEAR: 2020 DOI: 10.1029/2020JA027776 quasiperiodic VLF emissions; Cyclotron instability; wave propagation; Magnetosphere; whistler mode waves; Van Allen Probes |
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A Multi-Instrument Approach to Determining the Source-Region Extent of EEP-Driving EMIC Waves Abstract Recent years have seen debate regarding the ability of electromagnetic ion cyclotron (EMIC) waves to drive EEP (energetic electron precipitation) into the Earth s atmosphere. Questions still remain regarding the energies and rates at which these waves are able to interact with electrons. Many studies have attempted to characterize these interactions using simulations; however, these are limited by a lack of precise information regarding the spatial scale size of EMIC activity regions. In this study we examine a fort ... Hendry, A.; Santolik, O.; Miyoshi, Y.; Matsuoka, A.; Rodger, C.; Clilverd, M.; Kletzing, C.; Shoji, M.; Shinohara, I.; YEAR: 2020 DOI: 10.1029/2019GL086599 EMIC waves; electron precipitation; subionospheric VLF; Van Allen Probes; AARDDVARK; Arase |
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Plasmaspheric hiss is an important whistler-mode emission shaping the Van Allen radiation belt environment. How the plasmaspheric hiss waves are generated, propagate, and dissipate remains under intense debate. With the five spacecraft of Van Allen Probes, Exploration of energization and Radiation in Geospace (Arase), and Geostationary Operational Environmental Satellites missions at widely spaced locations, we present here the first comprehensive observations of hiss waves growing from the substorm-injected electron instabi ... Liu, Nigang; Su, Zhenpeng; Gao, Zhonglei; Zheng, Huinan; Wang, Yuming; Wang, Shui; Miyoshi, Yoshizumi; Shinohara, Iku; Kasahara, Yoshiya; Tsuchiya, Fuminori; Kumamoto, Atsushi; Matsuda, Shoya; Shoji, Masafumi; Mitani, Takefumi; Takashima, Takeshi; Kazama, Yoichi; Wang, Bo-Jhou; Wang, Shiang-Yu; Jun, Chae-Woo; Chang, Tzu-Fang; W. Y. Tam, Sunny; Kasahara, Satoshi; Yokota, Shoichiro; Keika, Kunihiro; Hori, Tomoaki; Matsuoka, Ayako; YEAR: 2020 DOI: 10.1029/2019GL086040 plasmasphere; Plasmaspheric Hiss; Radiation belt; Van Allen Probes; Wave Dissipation; wave generation; wave propagation |
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Direct evidence of the pitch angle scattering of relativistic electrons induced by EMIC waves In this study, we analyze an EMIC wave event of rising tone elements recorded by the Van Allen Probes. The pitch angle distributions of relativistic electrons exhibit a direct response to the two elements of EMIC waves: at the intermediate pitch angle the fluxes are lower and at the low pitch angle the fluxes are higher than those when no EMIC was observed. In particular, the observed changes in the pitch angle distributions are most likely to be caused by nonlinear wave particle interaction. The calculation of the minimum r ... Zhu, Hui; Chen, Lunjin; Claudepierre, Seth; Zheng, Liheng; YEAR: 2020 DOI: 10.1029/2019GL085637 EMIC waves; nonlinear wave-particle interaction; pitch angle scattering; Van Allen Probes |
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Direct evidence of the pitch angle scattering of relativistic electrons induced by EMIC waves In this study, we analyze an EMIC wave event of rising tone elements recorded by the Van Allen Probes. The pitch angle distributions of relativistic electrons exhibit a direct response to the two elements of EMIC waves: at the intermediate pitch angle the fluxes are lower and at the low pitch angle the fluxes are higher than those when no EMIC was observed. In particular, the observed changes in the pitch angle distributions are most likely to be caused by nonlinear wave particle interaction. The calculation of the minimum r ... Zhu, Hui; Chen, Lunjin; Claudepierre, Seth; Zheng, Liheng; YEAR: 2020 DOI: 10.1029/2019GL085637 EMIC waves; nonlinear wave-particle interaction; pitch angle scattering; Van Allen Probes |
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Episodic Occurrence of Field-Aligned Energetic Ions on the Dayside The tens of kiloelectron volt ions observed in the ring current region at L ~ 3\textendash7 generally have pancake pitch angle distributions, that is, peaked at 90\textdegree. However, in this study, by using the Van Allen Probe observations on the dayside, unexpectedly, we have found that about 5\% time, protons with energies of ~30 to 50 keV show two distinct populations, having an additional field-aligned population overlapping with the original pancake population. The newly appearing field-aligned populations have higher ... Yue, Chao; Bortnik, Jacob; Zou, Shasha; Nishimura, Yukitoshi; Foster, John; Coppeans, Thomas; Ma, Qianli; Zong, Qiugang; Hull, A.; Henderson, Mike; Reeves, Geoffrey; Spence, Harlan; YEAR: 2020 DOI: 10.1029/2019GL086384 |
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Abstract Plasmaspheric hiss is an important whistler-mode emission shaping the Van Allen radiation belt environment. How the plasmaspheric hiss waves are generated, propagate, and dissipate remains under intense debate. With the five spacecraft of Van Allen Probes, Exploration of energization and Radiation in Geospace (Arase), and Geostationary Operational Environmental Satellites missions at widely spaced locations, we present here the first comprehensive observations of hiss waves growing from the substorm-injected electro ... Liu, Nigang; Su, Zhenpeng; Gao, Zhonglei; Zheng, Huinan; Wang, Yuming; Wang, Shui; Miyoshi, Yoshizumi; Shinohara, Iku; Kasahara, Yoshiya; Tsuchiya, Fuminori; Kumamoto, Atsushi; Matsuda, Shoya; Shoji, Masafumi; Mitani, Takefumi; Takashima, Takeshi; Kazama, Yoichi; Wang, Bo-Jhou; Wang, Shiang-Yu; Jun, Chae-Woo; Chang, Tzu-Fang; W. Y. Tam, Sunny; Kasahara, Satoshi; Yokota, Shoichiro; Keika, Kunihiro; Hori, Tomoaki; Matsuoka, Ayako; YEAR: 2020 DOI: 10.1029/2019GL086040 Plasmaspheric Hiss; Radiation belt; plasmasphere; wave generation; wave propagation; Wave Dissipation |
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Statistical Dependence of EMIC Wave Scattering on Wave and Plasma Parameters Abstract A recent statistical study (Qin et al., 2018, https://doi.org/10.1029/2018JA025419) has suggested that not all electromagnetic ion cyclotron (EMIC) waves can scatter relativistic electrons. However, knowledge of the factors that influence the EMIC wave scattering efficiency is still limited in observations. In our study, we perform 6 years of analysis of data from 2013 to 2018, with relativistic electron precipitation (REP) observed by POES and EMIC wave observations from Van Allen Probes. The coincidence occurrence ... Qin, Murong; Hudson, Mary; Millan, Robyn; Woodger, Leslie; Shen, Xiaochen; YEAR: 2020 DOI: 10.1029/2020JA027772 EMIC waves; relativistic electron precipitation; coincidence occurrence rate; parametric dependence; Van Allen Probes |
| 2019 |
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On the Observation of Electrostatic Harmonics Associated With EMIC Waves In this study, we report two events of electrostatic harmonics associated with electromagnetic ion cyclotron (EMIC) waves recorded by the Van Allen Probes. Based on the wave and plasma measurements, the wave features are investigated and the possible generation mechanism is discussed. The frequencies of these electrostatic emissions are at the integer and fractional frequencies of the fundamental EMIC waves, which can be across and above the local proton gyrofrequencies. When the frequencies increase, the electric power spec ... YEAR: 2019 DOI: 10.1029/2019GL085528 |
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Direct Observation of Subrelativistic Electron Precipitation Potentially Driven by EMIC Waves Electromagnetic ion cyclotron (EMIC) waves are known to typically cause electron losses into Earth\textquoterights upper atmosphere at >~1 MeV, while the minimum energy of electrons subject to efficient EMIC-driven precipitation loss is unresolved. This letter reports electron precipitation from subrelativistic energies of ~250 keV up to ~1 MeV observed by the Focused Investigations of Relativistic Electron Burst Intensity, Range and Dynamics (FIREBIRD-II) CubeSats, while two Polar Operational Environmental Satellites (POES) ... Capannolo, L.; Li, W.; Ma, Q.; Chen, L.; Shen, X.-C.; Spence, H.; Sample, J.; Johnson, A.; Shumko, M.; Klumpar, D.; Redmon, R.; YEAR: 2019 DOI: 10.1029/2019GL084202 electron precipitation; EMIC waves; FIREBIRD-II; quasi linear theory; Radiation belts; Van Allen Probes; wave particle interactions |
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Direct Observation of Subrelativistic Electron Precipitation Potentially Driven by EMIC Waves Electromagnetic ion cyclotron (EMIC) waves are known to typically cause electron losses into Earth\textquoterights upper atmosphere at >~1 MeV, while the minimum energy of electrons subject to efficient EMIC-driven precipitation loss is unresolved. This letter reports electron precipitation from subrelativistic energies of ~250 keV up to ~1 MeV observed by the Focused Investigations of Relativistic Electron Burst Intensity, Range and Dynamics (FIREBIRD-II) CubeSats, while two Polar Operational Environmental Satellites (POES) ... Capannolo, L.; Li, W.; Ma, Q.; Chen, L.; Shen, X.-C.; Spence, H.; Sample, J.; Johnson, A.; Shumko, M.; Klumpar, D.; Redmon, R.; YEAR: 2019 DOI: 10.1029/2019GL084202 electron precipitation; EMIC waves; FIREBIRD-II; quasi linear theory; Radiation belts; Van Allen Probes; wave particle interactions |
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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 |
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Effects of a Realistic O + Source on Modeling the Ring Current We use the UNH-IMEF electric field model to simulate the convection of O+ from the near-earth plasma sheet into the ring current during the March 17, 2015 storm. Using Van Allen Probes data from the night side apogee, we reconstruct a realistic O+ source. Modeling this storm using the UNH-IMEF electric field and a dipole magnetic field has previously been found to have good agreement. Using the realistic source along with drift times and charge exchange loss from these results, we model an inbound pass near the peak of the s ... Menz, A.M.; Kistler, L.M.; Mouikis, C.G.; Spence, H.E.; Henderson, M.G.; YEAR: 2019 DOI: 10.1029/2019JA026859 |
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The magnetospheric driver of strong thermal emission velocity enhancement (STEVE) is investigated using conjugate observations when Van Allen Probes\textquoteright footprint directly crossed both STEVE and stable red aurora (SAR) arc. In the ionosphere, STEVE is associated with subauroral ion drift features, including electron temperature peak, density gradient, and westward ion flow. The SAR arc at lower latitudes corresponds to regions inside the plasmapause with isotropic plasma heating, which causes redline-only SAR emis ... Chu, Xiangning; Malaspina, David; Gallardo-Lacourt, Bea; Liang, Jun; Andersson, Laila; Ma, Qianli; Artemyev, Anton; Liu, Jiang; Ergun, Robert; Thaller, Scott; Akbari, Hassanali; Zhao, Hong; Larsen, Brian; Reeves, Geoffrey; Wygant, John; Breneman, Aaron; Tian, Sheng; Connors, Martin; Donovan, Eric; Archer, William; MacDonald, Elizabeth; YEAR: 2019 DOI: 10.1029/2019GL082789 aurora; kinetic Alfven wave; Plasmapause; STEVE; subauroral ion drift; table red auroral arc; Van Allen Probes |
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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 |
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Characteristics and Generation of Low-Frequency Magnetosonic Waves Below the Proton Gyrofrequency We report a Van Allen Probes observation of large-amplitude magnetosonic waves with the peak intensity below the proton gyrofrequency (fcp), which may potentially be misinterpreted as electromagnetic ion cyclotron waves. The frequency spacing of the wave harmonic structure suggests that these magnetosonic waves are excited at a distant source region and propagate radially inward. We also conduct a statistical analysis of low-frequency magnetosonic waves below fcp based on the Van Allen Probes data from October 2012 to Decemb ... Teng, Shangchun; Li, Wen; Tao, Xin; Ma, Qianli; Shen, Xiaochen; YEAR: 2019 DOI: 10.1029/2019GL085372 Below the proton gyrofrequency; Low frequency magnetosonic wave; Van Allen Probes; wave generation; Wave propagation characteristics |
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The Storm-Time Ring Current Response to ICMEs and CIRs Using Van Allen Probe Observations Using Van Allen Probe observations of the inner magnetosphere during geomagnetic storms driven by interplanetary coronal mass ejections (ICMEs) and corotating interaction regions (CIRs), we characterize the impact of these drivers on the storm-time ring current development. Using 25 ICME- and 35 CIR-driven storms, we have determined the ring current pressure development during the prestorm, main, early-recovery, and late-recovery storm phases, as a function of magnetic local time, L shell and ion species (H+, He+, and O+) ov ... Mouikis, C.; Bingham, S.; Kistler, L.; Farrugia, C.; Spence, H.; Reeves, G.; Gkioulidou, M.; Mitchell, D.; Kletzing, C.; YEAR: 2019 DOI: 10.1029/2019JA026695 ICME vs CI; R Ion composition; Ring Current Pressure; Storm phases; Van Allen Probes |
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Modeling the Electron Flux Enhancement and Butterfly Pitch Angle Distributions on L Shells <2.5 We analyze an energetic electron flux enhancement event in the inner radiation belt observed by Van Allen Probes during an intense geomagnetic storm. The energetic electron flux at L~1.5 increased by a factor of 3 with pronounced butterfly pitch angle distributions (PADs). Using a three-dimensional radiation belt model, we simulate the electron evolution under the impact of radial diffusion, local wave-particle interactions including hiss, very low frequency transmitters, and magnetosonic waves, as well as Coulomb scattering ... Hua, Man; Li, Wen; Ma, Qianli; Ni, Binbin; Nishimura, Yukitoshi; Shen, Xiao-Chen; Li, Haimeng; YEAR: 2019 DOI: 10.1029/2019GL084822 3-D radial belt modeling; Butterfly pitch angle distribution; Electron flux enhancement; inner belt and slot region; Inward radial diffusion; local wave-particle interactions; Van Allen Probes |
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Analyzing EMIC Waves in the Inner Magnetosphere Using Long-Term Van Allen Probes Observations With 64-month magnetic data from Van Allen Probes, we have studied not only the global distribution, wave normal angle (θ), and ellipticity (ε) of electromagnetic ion cyclotron (EMIC) waves, but also the dependence of their occurrence rates and magnetic amplitudes on the AE* index (the mean value of AE index over previous 1 hr). Our results show that H+ band waves are preferentially detected at 5 <= L <= 6.5, in the noon sector. They typically have small θ (<30\textdegree) and weakly left-hand polarization but become more ... Chen, Huayue; Gao, Xinliang; Lu, Quanming; Wang, Shui; YEAR: 2019 DOI: 10.1029/2019JA026965 A long-term statistical work; EMIC wave; inner magnetosphere; spatial distribution; Van Allen Probes; Van Allen Probes observation; Wave fundamental characters |
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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 |
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Temperature Dependence of Plasmaspheric Ion Composition We analyze a database of Dynamics Explorer-1 (DE-1) Retarding Ion Mass Spectrometer densities and temperatures to yield the first explicit measure of how cold ion concentration depends on temperature. We find that cold H+ and He+ concentrations have very weak dependence on temperature, but cold O+ ion concentration increases steeply as these ions become warmer. We demonstrate how this result can aid in analyzing composition data from other satellites without spacecraft potential mitigation, by applying the result to an examp ... Goldstein, J.; Gallagher, D.; Craven, P.; Comfort, R.; Genestreti, K.; Mouikis, C.; Spence, H.; Kurth, W.; Wygant, J.; Skoug, R.; Larsen, B.; Reeves, G.; De Pascuale, S.; YEAR: 2019 DOI: 10.1029/2019JA026822 composition; plasmasphere: ion; temperature; Van Allen Probes |
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Double-peak subauroral ion drifts (DSAIDs), characterized by two high-speed flow channels, is a newly identified flow structure in the subauroral ionosphere. He et al. (2016, https://doi.org/10.1002/2016GL069133) proposed that two region 2 field-aligned currents (R2 FACs) might cause the DSAIDs. However, the underlying physical process that drives the double R2 FACs is unknown. This study reports a DSAIDs event and reveals its magnetospheric drivers. Defense Meteorological Satellite Program F18 satellite observed DSAIDs in t ... Wei, Dong; Yu, Yiqun; He, Fei; YEAR: 2019 DOI: 10.1029/2019GL083186 |
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Statistical analysis on plasmatrough exohiss waves from the Van Allen Probes In this study using Van Allen Probe wave observations we investigate the statistical properties of exohiss waves, which are structureless whistler mode waves observed outside the plasmapause. The exohiss waves are identified based on the cold electron number density, frequency distribution, ellipticity, and wave normal angle. The statistical analysis on exohiss wave properties shows that exohiss waves prefer to occur over 3 Zhu, Hui; Gu, Wenyao; Chen, Lunjin; YEAR: 2019 DOI: 10.1029/2018JA026359 |
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High energy trapped particles in the radiation belts constitute potential threats to the functionality of satellites as they enter into those regions. In the inner radiation belt, the characteristics of high-energy (>20MeV) protons variations during geomagnetic activity times have been studied by implementing four-year (2013-2016) observations of the Van Allen probes. An empirical formula has been used to remove the satellite orbit effect, by which proton fluxes have been normalized to the geomagnetic equator. Case studies s ... Xu, Jiyao; He, Zhaohai; Baker, D.N.; Roth, Ilan; Wang, C.; Kanekal, S.G.; Jaynes, A.N.; Liu, Xiao; YEAR: 2019 DOI: 10.1029/2018JA026205 geomagnetic activities; high energy proton; Inner radiation belt; one-to-one correspondence; prompt responses; RBSP satellite; Van Allen Probes |
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A Pc5 wave was simultaneously observed in the ionosphere by EKB radar and in the magnetosphere by both Van Allen Probe spacecraft within a substorm activity. The wave was located in the nightside, in 1.5- to 3-hr magnetic local time sector, and in the region corresponding to the magnetic shells with maximal distances 4.6\textendash7.8 Earth\textquoterights radii. As it was found using both the radar and spacecraft data, the wave had frequency of about 1.8 mHz and azimuthal wave number m≈-10; that is, the wave was westward ... Mager, Olga; Chelpanov, Maksim; Mager, Pavel; Klimushkin, Dmitri; Berngardt, Oleg; YEAR: 2019 DOI: 10.1029/2019JA026541 compressional waves; Pc5; poloidal waves; SUPERDARN; ULF waves; Van Allen Probes |
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Effects of scattering of electrons from whistler chorus waves and of ions due to field line curvature on diffuse precipitating particle fluxes and ionospheric conductance during the large 17 March 2013 storm are examined using the self-consistent Rice Convection Model Equilibrium (RCM-E) model. Electrons are found to dominate the diffuse precipitating particle integrated energy flux, with large fluxes from ~21:00 magnetic local time (MLT) eastward to ~11:00 MLT during the storm main phase. Simulated proton and oxygen ion pre ... Chen, Margaret; Lemon, Colby; Hecht, James; Sazykin, Stanislav; Wolf, Richard; Boyd, Alexander; Valek, Philip; YEAR: 2019 DOI: 10.1029/2019JA026545 diffuse aurora; electron and ion precipitation; field-line curvature scattering; inner magnetospheric electric field; ionospheric conductance; simulations and data comparisons; Van Allen Probes |
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Effects of scattering of electrons from whistler chorus waves and of ions due to field line curvature on diffuse precipitating particle fluxes and ionospheric conductance during the large 17 March 2013 storm are examined using the self-consistent Rice Convection Model Equilibrium (RCM-E) model. Electrons are found to dominate the diffuse precipitating particle integrated energy flux, with large fluxes from ~21:00 magnetic local time (MLT) eastward to ~11:00 MLT during the storm main phase. Simulated proton and oxygen ion pre ... Chen, Margaret; Lemon, Colby; Hecht, James; Sazykin, Stanislav; Wolf, Richard; Boyd, Alexander; Valek, Philip; YEAR: 2019 DOI: 10.1029/2019JA026545 diffuse aurora; electron and ion precipitation; field-line curvature scattering; inner magnetospheric electric field; ionospheric conductance; simulations and data comparisons; Van Allen Probes |
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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 |
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In this study, rapid loss of relativistic radiation belt electrons at low L* values (2.4\textendash3.2) during a strong geomagnetic storm on 22 June 2015 is investigated along with five possible loss mechanisms. Both the particle and wave data are obtained from the Van Allen Probes. Duskside H+ band electromagnetic ion cyclotron (EMIC) waves were observed during a rapid decrease of relativistic electrons with energy above 5.2 MeV occurring outside the plasmasphere during extreme magnetopause compression. Lower He+ compositio ... Qin, Murong; Hudson, Mary; Li, Zhao; Millan, Robyn; Shen, Xiaochen; Shprits, Yuri; Woodger, Leslie; Jaynes, Allison; Kletzing, Craig; YEAR: 2019 DOI: 10.1029/2018JA025726 cold ion composition; EMIC wave; minimum resonant energy; pitch angle diffusion; quasi-linear theory; relativistic electron loss; Van Allen Probes |
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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 |
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Chorus waves are known to accelerate or scatter energetic electrons via quasi-linear or nonlinear wave-particle interactions in the Earth\textquoterights magnetosphere. In this letter, by taking advantage of simultaneous observations of chorus waveforms from at least a pair of probes among Van Allen Probes and/or Time History of Events and Macroscale Interactions during Substorms (THEMIS) missions, we statistically calculate the transverse size of lower band chorus wave elements. The average size of lower band chorus wave el ... Shen, Xiao-Chen; Li, Wen; Ma, Qianli; Agapitov, Oleksiy; Nishimura, Yukitoshi; YEAR: 2019 DOI: 10.1029/2019GL083118 |
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Triggered Plasmaspheric Hiss: Rising Tone Structures In this study, a rare hiss event observed by Van Allen Probe is reported and the possible generation is investigated based on wave and plasma measurements. The results suggest that the normal hiss (from 0.05fce to 0.5fce) with dominantly equatorward Poynting fluxes is locally generated by plasma sheet electrons via cyclotron instability. The low-frequency band (from 30 Hz to 0.05fce) with a mixture of equatorward and poleward Poynting fluxes is probably due to multiple reflections inside the plasmasphere. Such difference in ... Zhu, Hui; Liu, Xu; Chen, Lunjin; YEAR: 2019 DOI: 10.1029/2019GL082688 Plasmaspheric Hiss; Radiation belts; Rising tone structure; Van Allen Probes |
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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 |
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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 |
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Investigation of Solar Proton Access into the inner magnetosphere on 11 September 2017 In this study, access of solar energetic protons to the inner magnetosphere on 11 September 2017 is investigated by computing the reverse particle trajectories with the Dartmouth geomagnetic cutoff code [Kress et al., 2010]. The maximum and minimum cutoff rigidity at each point along the orbit of Van Allen Probe A is numerically computed by extending the code to calculate cutoff rigidity for particles coming from arbitrary direction. Pulse-height analyzed (PHA) data has the advantage of providing individual particle energies ... Qin, Murong; Hudson, Mary; Kress, Brian; Selesnick, Richard; Engel, Miles; Li, Zhao; Shen, Xiaochen; YEAR: 2019 DOI: 10.1029/2018JA026380 cutoff energy; cutoff location; Dartmouth geomagnetic cutoff code; Pulse height analyzed data; Solar proton; straggling function; Van Allen Probes |
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Modulation of Locally Generated Equatorial Noise by ULF Wave In this paper we report a rare and fortunate event of fast magnetosonic (MS, also called equatorial noise) waves modulated by compressional ultralow frequency (ULF) waves measured by Van Allen Probes. The characteristics of MS waves, ULF waves, proton distribution, and their potential correlations are analyzed. The results show that ULF waves can modulate the energetic ring proton distribution and in turn modulate the MS generation. Furthermore, the variation of MS intensities is attributed to not only ULF wave activities bu ... Zhu, Hui; Chen, Lunjin; Liu, Xu; Shprits, Yuri; YEAR: 2019 DOI: 10.1029/2018JA026199 linear growth rate; magnetosonic waves; Radiation belts; ULF waves; Van Allen Probes |
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We report on evidence for the generation of an ultra-low frequency plasma wave by the drift-mirror plasma instability in the dynamic plasma environment of Earth\textquoterights inner magnetosphere. The plasma measurements are obtained from the Radiation Belt Storm Probes Ion Composition Experiment onboard NASA\textquoterights Van Allen Probes Satellites. We show that the measured wave-particle interactions are driven by the drift-mirror instability. Theoretical analysis of the data demonstrates that the drift-mirror mode pla ... Soto-Chavez, A.; Lanzerotti, L.; Manweiler, J.; Gerrard, A.; Cohen, R.; Xia, Z.; Chen, L.; Kim, H.; YEAR: 2019 DOI: 10.1063/1.5083629 |
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We report on evidence for the generation of an ultra-low frequency plasma wave by the drift-mirror plasma instability in the dynamic plasma environment of Earth\textquoterights inner magnetosphere. The plasma measurements are obtained from the Radiation Belt Storm Probes Ion Composition Experiment onboard NASA\textquoterights Van Allen Probes Satellites. We show that the measured wave-particle interactions are driven by the drift-mirror instability. Theoretical analysis of the data demonstrates that the drift-mirror mode pla ... Soto-Chavez, A.; Lanzerotti, L.; Manweiler, J.; Gerrard, A.; Cohen, R.; Xia, Z.; Chen, L.; Kim, H.; YEAR: 2019 DOI: 10.1063/1.5083629 |
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Plasma kinetic theory predicts that sufficiently anisotropic proton distribution will excite electromagnetic ion cyclotron (EMIC) waves, which in turn relax the proton distribution to a marginally stable state creating an upper bound on the relaxed proton anisotropy. Here, using EMIC wave observations and coincident plasma measurements made by Van Allen Probes in the inner magnetosphere, we show that the proton distributions are well constrained by this instability to a marginally stable state. Near the threshold, the probab ... Yue, Chao; Jun, Chae-Woo; Bortnik, Jacob; An, Xin; Ma, Qianli; Reeves, Geoffrey; Spence, Harlan; Gerrard, Andrew; Gkioulidou, Matina; Mitchell, Donald; Kletzing, Craig; YEAR: 2019 DOI: 10.1029/2019GL082633 EMIC waves; helium-band; hydrogen-band; plasma beta; proton temperature anisotropy; Van Allen Probes |
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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 |
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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 |
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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 |
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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 |
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Energy coupling between the solar wind and the Earth\textquoterights magnetosphere can affect the electron population in the outer radiation belt. However, the precise role of different internal and external mechanisms that leads to changes of the relativistic electron population is not entirely known. This paper describes how Ultra Low Frequency (ULF) wave activity during the passage of Alfv\ enic solar wind streams contributes to the global recovery of the relativistic electron population in the outer radiation belt. To in ... Da Silva, L.; Sibeck, D.; Alves, L.; Souza, V.; Jauer, P.; Claudepierre, S.; Marchezi, J.; Agapitov, O.; Medeiros, C.; Vieira, L.; Wang, C.; Jiankui, S.; Liu, Z.; Gonzalez, W.; Dal Lago, A.; Rockenbach, M.; Padua, M.; Alves, M.; Barbosa, M.; Fok, M.-C.; Baker, D.; Kletzing, C.; Kanekal, S.; Georgiou, M.; YEAR: 2019 DOI: 10.1029/2018JA026184 alfv\ en fluctuations; Earth\textquoterights magnetosphere; high speed stream; Radiation belts; relativistic electron flux; ULF wave; Van Allen Probes |
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Initial Results From the GEM Challenge on the Spacecraft Surface Charging Environment Spacecraft surface charging during geomagnetically disturbed times is one of the most important causes of satellite anomalies. Predicting the surface charging environment is one prevalent task of the geospace environment models. Therefore, the Geospace Environment Modeling (GEM) Focus Group \textquotedblleftInner Magnetosphere Cross-energy/Population Interactions\textquotedblright initiated a community-wide challenge study to assess the capability of several inner magnetosphere ring current models in determining surface char ... Yu, Yiqun; ätter, Lutz; Jordanova, Vania; Zheng, Yihua; Engel, Miles; Fok, Mei-Ching; Kuznetsova, Maria; YEAR: 2019 DOI: 10.1029/2018SW002031 GEM challenge; IMCEPI Focus Group; ring current model assessment; Space weather; spacecraft surface charging; Van Allen Probes |
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This work designs a new model called PreMevE to predict storm-time distributions of relativistic electrons within Earth\textquoterights outer radiation belt. This model takes advantage of the cross-energy, -L-shell, and \textendashpitch-angle coherence associated with wave-electron resonant interactions, ingests observations from belt boundaries\textemdashmainly by NOAA POES in low-Earth-orbits (LEOs), and provides high-fidelity nowcast (multiple-hour prediction) and forecast (> ~1 day) of MeV electron fluxes over L-shells b ... Chen, Yue; Reeves, Geoffrey; Fu, Xiangrong; Henderson, Michael; YEAR: 2019 DOI: 10.1029/2018SW002095 event-specific predictions; LANL GEO observations; linear predictive filters; MeV electron events; outer radiation belt; precipitation at low-earth-orbits (LEO); Van Allen Probes |
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This work designs a new model called PreMevE to predict storm-time distributions of relativistic electrons within Earth\textquoterights outer radiation belt. This model takes advantage of the cross-energy, -L-shell, and \textendashpitch-angle coherence associated with wave-electron resonant interactions, ingests observations from belt boundaries\textemdashmainly by NOAA POES in low-Earth-orbits (LEOs), and provides high-fidelity nowcast (multiple-hour prediction) and forecast (> ~1 day) of MeV electron fluxes over L-shells b ... Chen, Yue; Reeves, Geoffrey; Fu, Xiangrong; Henderson, Michael; YEAR: 2019 DOI: 10.1029/2018SW002095 event-specific predictions; LANL GEO observations; linear predictive filters; MeV electron events; outer radiation belt; precipitation at low-earth-orbits (LEO); Van Allen Probes |
