Bibliography





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Found 32 entries in the Bibliography.


Showing entries from 1 through 32


2021

A Statistical Study of Low-Energy Ion Flux Enhancements by EMIC Waves in the Inner Magnetosphere

Abstract We have studied the statistical properties of low-energy proton (H+) and helium (He+) ion flux enhancements associated with EMIC waves in the inner magnetosphere using Van Allen Probes data for 2013-2017. We identified 167 low-energy ion flux enhancements when the EMIC waves occurred in a He-band or in a multiple band (H-band and He-band) with strong He-band and weak H-band wave activity and found that most of them occurred from the noon to the premidnight sector near the magnetic equator just inside the plasmapause ...

Lee, Junhyun; Kim, Khan-Hyuk; Lee, Ensang;

Published by: Journal of Geophysical Research: Space Physics      Published on: 08/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029793

Van Allen Probes

A Statistical Study of Low-Energy Ion Flux Enhancements by EMIC Waves in the Inner Magnetosphere

Abstract We have studied the statistical properties of low-energy proton (H+) and helium (He+) ion flux enhancements associated with EMIC waves in the inner magnetosphere using Van Allen Probes data for 2013-2017. We identified 167 low-energy ion flux enhancements when the EMIC waves occurred in a He-band or in a multiple band (H-band and He-band) with strong He-band and weak H-band wave activity and found that most of them occurred from the noon to the premidnight sector near the magnetic equator just inside the plasmapause ...

Lee, Junhyun; Kim, Khan-Hyuk; Lee, Ensang;

Published by: Journal of Geophysical Research: Space Physics      Published on: 08/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029793

Van Allen Probes

Rapid injections of MeV electrons and extremely fast step-like outer radiation belt enhancements

Abstract Rapid injection of MeV electrons associated with strong substorm dipolarization has been suggested as a potential explanation for some radiation belt enhancement events. However, it has been difficult to quantify the contribution of MeV electron injections to radiation belt enhancements. This paper presents two isolated MeV electron injection events for which we quite precisely quantify how the entire outer-belt immediately changed with the injections. Tracking detailed outer-belt evolution observed by Van Allen Pro ...

Kim, H.-J.; Lee, D.-Y.; Wolf, R.; Bortnik, J.; Kim, K.-C.; Lyons, L.; Choe, W.; Noh, S.-J.; Choi, K.-E.; Yue, C.; Li, J.;

Published by: Geophysical Research Letters      Published on: 05/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL093151

Radiation belt enhancement; Relatvistic electrons; substorm injection; Step-like; Extremely fast; Van Allen Probes

Upper limit of proton anisotropy and its relation to EMIC waves in the inner magnetosphere

Abstract Proton anisotropy in velocity space has been generally accepted as a major parameter for exciting electromagnetic ion cyclotron (EMIC) waves. In this study, we estimate the proton anisotropy parameter as defined by the linear resonance theory using data from the Van Allen Probes mission. Our investigation uses the measurements of the inner magnetosphere (L < 6) from January 2013 to February 2018. We find that the proton anisotropy is always clearly limited by an upper bound and it well follows an inverse relationshi ...

Noh, Sung-Jun; Lee, Dae-Young; Kim, Hyomin; Lanzerotti, Louis; Gerrard, Andrew; Skoug, Ruth;

Published by: Journal of Geophysical Research: Space Physics      Published on: 04/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2020JA028614

Proton Anisotropy; Ion cyclotron instability; Proton distribution; Van Allen Probes; Wave-particle interaction

A Case Study of Transversely Heated Low-Energy Helium Ions by EMIC Waves in the Plasmasphere

Abstract The Van Allen Probe A spacecraft observed strong ∼0.5-Hz helium (He+) band and weak ∼0.8-Hz hydrogen (H+) band EMIC waves on April 17, 2018, at L = ∼4.5–5.2, in the dawn sector, near the magnetic equator, and close to the plasmapause. We examined low-energy ion fluxes observed by the Helium Oxygen Proton and Electron (HOPE) instrument onboard Van Allen Probe A during the wave interval and found that low-energy He+ flux (<10 eV) enhancements occur nearly simultaneously with He-band and H-band EMIC wave pow ...

Kim, Khan-Hyuk; Kwon, Hyuck-Jin; Lee, Junhyun; Jin, Ho; Seough, Jungjoon;

Published by: Journal of Geophysical Research: Space Physics      Published on: 02/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2020JA028560

Van Allen Probes

Observations of Particle Loss due to Injection-Associated EMIC Waves

AbstractWe report on observations of electromagnetic ion cyclotron (EMIC) waves and their interactions with injected ring current particles and high energy radiation belt electrons. The magnetic field experiment aboard the twin Van Allen Probes spacecraft measured EMIC waves near L = 5.5 − 6. Particle data from the spacecraft show that the waves were associated with particle injections. The wave activity was also observed by a ground-based magnetometer near the spacecraft geomagnetic footprint over a more extensive tempora ...

Kim, Hyomin; Schiller, Quintin; Engebretson, Mark; Noh, Sungjun; Kuzichev, Ilya; Lanzerotti, Louis; Gerrard, Andrew; Kim, Khan-Hyuk; Lessard, Marc; Spence, Harlan; Lee, Dae-Young; Matzka, Jürgen; Fromm, Tanja;

Published by: Journal of Geophysical Research: Space Physics      Published on: 01/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2020JA028503

EMIC waves; ring current; Radiation belt; wave particle interaction; injection; Particle precipitation; Van Allen Probes

2018

Roles of Flow Braking, Plasmaspheric Virtual Resonances, and Ionospheric Currents in Producing Ground Pi2 Pulsations

In one model, Pi2 pulsations are driven pulse by pulse by fast mode pulses that are launched as periodic bursty bulk flows brake when they approach the Earth. We have examined this model by analyzing data from multiple spacecraft and ground magnetometers for a Pi2 pulsation event. During the event, which started at \~2226 UT on 8 November 2014, Time History of Events and Macroscale Interactions during Substorms (THEMIS)-D detected an \~2 min period plasma bulk flow oscillation in the near-Earth magnetotail, while THEMIS-E an ...

Takahashi, Kazue; Hartinger, Michael; Vellante, Massimo; Heilig, azs; Lysak, Robert; Lee, Dong-Hun; Smith, Charles;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2018

YEAR: 2018     DOI: 10.1029/2018JA025664

Van Allen Probes

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;

Published by: Journal of Geophysical Research: Space Physics      Published on: 08/2018

YEAR: 2018     DOI: 10.1029/2018JA025385

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

Space Weather Operation at KASI with Van Allen Probes Beacon Signals

The Van Allen Probes (VAPs) are the only modern NASA spacecraft broadcasting real-time data on the Earth\textquoterights radiation belts for space weather operations. Since 2012, the Korea Astronomy and Space Science Institute (KASI) has contributed to the receipt of this data via a 7-m satellite tracking antenna and used these data for space weather operations. An approximately 15-min period is required from measurement to acquisition of Level-1 data. In this paper, we demonstrate the use of VAP data for monitoring space we ...

Lee, Jongkil; Kim, Kyung-Chan; Romeo, Giuseppe; Ukhorskiy, Sasha; Sibeck, David; Kessel, Ramona; Mauk, Barry; Giles, Barbara; Gu, Bon-Jun; Lee, Hyesook; Park, Young-Deuk; Lee, Jaejin;

Published by: Space Weather      Published on: 01/2018

YEAR: 2018     DOI: 10.1002/2017SW001726

Electron acceleration; Radiation belt; Relativistic electron; Space weather; Van Allen Probes

Space Weather Operation at KASI with Van Allen Probes Beacon Signals

The Van Allen Probes (VAPs) are the only modern NASA spacecraft broadcasting real-time data on the Earth\textquoterights radiation belts for space weather operations. Since 2012, the Korea Astronomy and Space Science Institute (KASI) has contributed to the receipt of this data via a 7-m satellite tracking antenna and used these data for space weather operations. An approximately 15-min period is required from measurement to acquisition of Level-1 data. In this paper, we demonstrate the use of VAP data for monitoring space we ...

Lee, Jongkil; Kim, Kyung-Chan; Romeo, Giuseppe; Ukhorskiy, Sasha; Sibeck, David; Kessel, Ramona; Mauk, Barry; Giles, Barbara; Gu, Bon-Jun; Lee, Hyesook; Park, Young-Deuk; Lee, Jaejin;

Published by: Space Weather      Published on: 01/2018

YEAR: 2018     DOI: 10.1002/2017SW001726

Electron acceleration; Radiation belt; Relativistic electron; Space weather; Van Allen Probes

Space Weather Operation at KASI with Van Allen Probes Beacon Signals

The Van Allen Probes (VAPs) are the only modern NASA spacecraft broadcasting real-time data on the Earth\textquoterights radiation belts for space weather operations. Since 2012, the Korea Astronomy and Space Science Institute (KASI) has contributed to the receipt of this data via a 7-m satellite tracking antenna and used these data for space weather operations. An approximately 15-min period is required from measurement to acquisition of Level-1 data. In this paper, we demonstrate the use of VAP data for monitoring space we ...

Lee, Jongkil; Kim, Kyung-Chan; Romeo, Giuseppe; Ukhorskiy, Sasha; Sibeck, David; Kessel, Ramona; Mauk, Barry; Giles, Barbara; Gu, Bon-Jun; Lee, Hyesook; Park, Young-Deuk; Lee, Jaejin;

Published by: Space Weather      Published on: 01/2018

YEAR: 2018     DOI: 10.1002/2017SW001726

Electron acceleration; Radiation belt; Relativistic electron; Space weather; Van Allen Probes

2017

Examining coherency scales, substructure, and propagation of whistler-mode chorus elements with Magnetospheric Multiscale (MMS)

Whistler-mode chorus waves are a naturally occurring electromagnetic emission observed in Earth\textquoterights magnetosphere. Here, for the first time, data from NASA\textquoterights Magnetospheric Multiscale (MMS) mission were used to analyze chorus waves in detail, including the calculation of chorus wave normal vectors, k. A case study was examined from a period of substorm activity around the time of a conjunction between the MMS constellation and NASA\textquoterights Van Allen Probes mission on 07 April 2016. Chorus wa ...

Turner, D.; Lee, J.; Claudepierre, S.; Fennell, J.; Blake, J.; Jaynes, A.; Leonard, T.; Wilder, F.; Ergun, R.; Baker, D.; Cohen, I.; Mauk, B.; Strangeway, R.; Hartley, D.; Kletzing, C.; Breuillard, H.; Le Contel, O.; Khotyaintsev, Yu; Torbert, R.; Allen, R.; Burch, J.; Santolik, O.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2017

YEAR: 2017     DOI: 10.1002/2017JA024474

chorus waves; inner magnetosphere; Magnetospheric multiscale; MMS; Radiation belts; Van Allen Probes

SC-associated electric field variations in the magnetosphere and ionospheric convective flows

We examine magnetic and electric field perturbations associated with a sudden commencement (SC), caused by an interplanetary (IP) shock passing over the Earth\textquoterights magnetosphere on 16 February 2013. The SC was identified in the magnetic and electric field data measured at THEMIS-E (THE-E: MLT = 12.4, L = 6.3), Van Allen Probe-A (VAP-A: MLT = 3.2, L = 5.1), and Van Allen Probe-B (VAP-B: MLT = 0.2. L= 4.9) in the magnetosphere. During the SC interval, THE-E observed a dawnward-then-duskward electric (E) field pertur ...

Kim, S.-I.; Kim, K.-H.; Kwon, H.-J.; Jin, H.; Lee, E.; Jee, G.; Nishitani, N.; Hori, T.; Lester, M.; Wygant, J.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2017

YEAR: 2017     DOI: 10.1002/2017JA024611

electric field; Sudden commencement; Van Allen Probes

Roles of hot electrons in generating upper-hybrid waves in the earth\textquoterights radiation belt

Electrostatic fluctuations near upper-hybrid frequency, which are sometimes accompanied by multiple-harmonic electron cyclotron frequency bands above and below the upper-hybrid frequency, are common occurrences in the Earth\textquoterights radiation belt, as revealed through the twin Van Allen Probe spacecrafts. It is customary to use the upper-hybrid emissions for estimating the background electron density, which in turn can be used to determine the plasmapause locations, but the role of hot electrons in generating such flu ...

Hwang, J.; Shin, D.; Yoon, P.; Kurth, W.; Larsen, B.; Reeves, G.; . Y. Lee, D;

Published by: Physics of Plasmas      Published on: 06/2017

YEAR: 2017     DOI: 10.1063/1.4984249

Hot carriers; Magnetized plasmas; Radiation belts; Singing; Van Allen Probes; Whistler waves

Spatial dependence of electromagnetic ion cyclotron waves triggered by solar wind dynamic pressure enhancements

In this paper, using the multisatellite (the Van Allen Probes and two GOES satellites) observations in the inner magnetosphere, we examine two electromagnetic ion cyclotron (EMIC) wave events that are triggered by Pdyn enhancements under prolonged northward interplanetary magnetic field quiet time preconditions. For both events, the impact of enhanced Pdyn causes EMIC waves at multiple points. However, we find a strong spatial dependence that EMIC waves due to enhanced Pdyn impact can occur at multiple points (likely globall ...

Cho, J.-H.; Lee, D.-Y.; Noh, S.-J.; Kim, H.; Choi, C.; Lee, J.; Hwang, J.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2017

YEAR: 2017     DOI: 10.1002/2016JA023827

Dynamic pressure; EMIC waves; Van Allen Probes

Spatial dependence of electromagnetic ion cyclotron waves triggered by solar wind dynamic pressure enhancements

In this paper, using the multisatellite (the Van Allen Probes and two GOES satellites) observations in the inner magnetosphere, we examine two electromagnetic ion cyclotron (EMIC) wave events that are triggered by Pdyn enhancements under prolonged northward interplanetary magnetic field quiet time preconditions. For both events, the impact of enhanced Pdyn causes EMIC waves at multiple points. However, we find a strong spatial dependence that EMIC waves due to enhanced Pdyn impact can occur at multiple points (likely globall ...

Cho, J.-H.; Lee, D.-Y.; Noh, S.-J.; Kim, H.; Choi, C.; Lee, J.; Hwang, J.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2017

YEAR: 2017     DOI: 10.1002/2016JA023827

Dynamic pressure; EMIC waves; Van Allen Probes

2016

Van Allen Probes Observations of Electromagnetic Ion Cyclotron Waves Triggered by Enhanced Solar Wind Dynamic Pressure

Magnetospheric compression due to impact of enhanced solar wind dynamic pressure Pdyn has long been considered as one of the generation mechanisms of electromagnetic ion cyclotron (EMIC) waves. With the Van Allen Probe-A observations, we identify three EMIC wave events that are triggered by Pdyn enhancements under prolonged northward IMF quiet time preconditions. They are in contrast to one another in a few aspects. Event 1 occurs in the middle of continuously increasing Pdyn while Van Allen Probe-A is located outside the pl ...

Cho, J.-H.; Lee, D.-Y.; Noh, S.-J.; Shin, D.-K.; Hwang, J.; Kim, K.-C.; Lee, J.; Choi, C.; Thaller, S.; Skoug, R.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2016

YEAR: 2016     DOI: 10.1002/2016JA022841

Dynamic pressure; EMIC waves; Van Allen Probes

Van Allen Probes Observations of Electromagnetic Ion Cyclotron Waves Triggered by Enhanced Solar Wind Dynamic Pressure

Magnetospheric compression due to impact of enhanced solar wind dynamic pressure Pdyn has long been considered as one of the generation mechanisms of electromagnetic ion cyclotron (EMIC) waves. With the Van Allen Probe-A observations, we identify three EMIC wave events that are triggered by Pdyn enhancements under prolonged northward IMF quiet time preconditions. They are in contrast to one another in a few aspects. Event 1 occurs in the middle of continuously increasing Pdyn while Van Allen Probe-A is located outside the pl ...

Cho, J.-H.; Lee, D.-Y.; Noh, S.-J.; Shin, D.-K.; Hwang, J.; Kim, K.-C.; Lee, J.; Choi, C.; Thaller, S.; Skoug, R.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2016

YEAR: 2016     DOI: 10.1002/2016JA022841

Dynamic pressure; EMIC waves; Van Allen Probes

2015

Simultaneous Pi2 observations by the Van Allen Probes inside and outside the plasmasphere

Plasmaspheric virtual resonance (PVR) model has been proposed as one of source mechanisms for low-latitude Pi2 pulsations. Since PVR-associated Pi2 pulsations are not localized inside the plasmasphere, simultaneous multipoint observations inside and outside the plasmasphere require to test the PVR model. Until now, however, there are few studies using simultaneous multisatellite observations inside and outside the plasmasphere for understanding the radial structure of Pi2 pulsation. In this study, we focus on the Pi2 event o ...

Ghamry, E.; Kim, K.-H.; Kwon, H.-J.; Lee, D.-H.; Park, J.-S.; Choi, J.; Hyun, K.; Kurth, W.; Kletzing, C.; Wygant, J.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2015

YEAR: 2015     DOI: 10.1002/2015JA021095

Pi2; plasmasphere; Plasmaspheric virtual resonance; Van Allen Probes

Comprehensive analysis of the flux dropout during 7-8 November 2008 storm using multi-satellites observations and RBE model

We investigate an electron flux dropout during a weak storm on 7\textendash8 November 2008, with Dst minimum value being -37 nT. During this period, two clear dropouts were observed on GOES 11 > 2 MeV electrons. We also find a simultaneous dropout in the subrelativistic electrons recorded by Time History of Events and Macroscale Interactions during Substorms probes in the outer radiation belt. Using the Radiation Belt Environment model, we try to reproduce the observed dropout features in both relativistic and subrelativisti ...

Hwang, J.; Choi, E.-J.; Park, J.-S.; Fok, M.-C.; Lee, D.-Y.; Kim, K.-C.; Shin, D.-K.; Usanova, M.; Reeves, G.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2015

YEAR: 2015     DOI: 10.1002/2015JA021085

atmospheric precipitation; flux dropout; Geomagnetic storm; magneopause shadowing; Radiation belt; RBE model

New model fit functions of the plasmapause location determined using THEMIS observations during the ascending phase of Solar Cycle 24

It is well known that the plasmapause is influenced by the solar wind and magnetospheric conditions. Empirical models of its location have been previously developed such as those by O\textquoterightBrien and Moldwin (2003) and Larsen et al. (2006). In this study, we identified the locations of the plasmapause using the plasma density data obtained from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites. We used the data for the period (2008\textendash2012) corresponding to the ascendi ...

Cho, Junghee; Lee, Dae-Young; Kim, Jin-Hee; Shin, Dae-Kyu; Kim, Kyung-Chan; Turner, Drew;

Published by: Journal of Geophysical Research: Space Physics      Published on: 04/2015

YEAR: 2015     DOI: 10.1002/2015JA021030

Plasmapause; THEMIS

A prediction model for the global distribution of whistler chorus wave amplitude developed separately for two latitudinal zones

Whistler mode chorus waves are considered to play a central role in accelerating and scattering electrons in the outer radiation belt. While in situ measurements are usually limited to the trajectories of a small number of satellites, rigorous theoretical modeling requires a global distribution of chorus wave characteristics. In the present work, by using a large database of chorus wave observations made on the Time History of Events and Macroscale Interactions during Substorms satellites for about 5 years, we develop predic ...

Kim, Jin-Hee; Lee, Dae-Young; Cho, Jung-Hee; Shin, Dae-Kyu; Kim, Kyung-Chan; Li, Wen; Kim, Thomas;

Published by: Journal of Geophysical Research: Space Physics      Published on: 04/2015

YEAR: 2015     DOI: 10.1002/2014JA020900

Radiation belt; whistler chorus

The global context of the 14 November, 2012 storm event

From 2 to 5 UT on 14 November, 2012, the Van Allen Probes observed repeated particle flux dropouts during the main phase of a geomagnetic storm as the satellites traversed the post-midnight to dawnside inner magnetosphere. Each flux dropout corresponded to an abrupt change in the magnetic topology, i.e., from a more dipolar configuration to a configuration with magnetic field lines stretched in the dawn-dusk direction. Geosynchronous GOES spacecraft located in the dusk and near-midnight sectors and the LANL constellation wit ...

Hwang, K.-J.; Sibeck, D.; Fok, M.-C.; Zheng, Y.; Nishimura, Y.; Lee, J.-J.; Glocer, A.; Partamies, N.; Singer, H.; Reeves, G.; Mitchell, D.; Kletzing, C.; Onsager, T.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 02/2015

YEAR: 2015     DOI: 10.1002/2014JA020826

Van Allen Probes

2014

Observations and modeling of EMIC wave properties in the presence of multiple ion species as function of magnetic local time

Electromagnetic ion cyclotron (EMIC) wave generation and propagation in Earth\textquoterights magnetosphere depend on readily measurable hot (a few to tens of keV) plasma sheet ions, elusive plasmaspheric or ionospheric cold (sub-eV to a few eV) ions, and partially heated warm ions (tens to hundreds of eV). Previous work has assumed all low-energy ions are cold and not considered possible effects of warm ions. Using measurements by multiple Time History of Events and Macroscale Interactions during Substorms spacecraft, we an ...

Lee, Justin; Angelopoulos, Vassilis;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/2014JA020469

EMIC waves; ion composition; ion cyclotron waves; low-energy ions; THEMIS; warm plasma effects

Ground-based ELF/VLF chorus observations at subauroral latitudes-VLF-CHAIN Campaign

We report observations of very low frequency (VLF) and extremely low frequency (ELF) chorus waves taken during the ELF/VLF Campaign observation with High-resolution Aurora Imaging Network (VLF-CHAIN) of 17\textendash25 February 2012 at subauroral latitudes at Athabasca (L=4.3), Canada. ELF/VLF waves were measured continuously with a sampling rate of 100 kHz to monitor daily variations in ELF/VLF emissions and derive their detailed structures. We found quasiperiodic (QP) emissions whose repetition period changes rapidly withi ...

Shiokawa, Kazuo; Yokoyama, Yu; Ieda, Akimasa; Miyoshi, Yoshizumi; Nomura, Reiko; Lee, Sungeun; Sunagawa, Naoki; Miyashita, Yukinaga; Ozaki, Mitsunori; Ishizaka, Kazumasa; Yagitani, Satoshi; Kataoka, Ryuho; Tsuchiya, Fuminori; Schofield, Ian; Connors, Martin;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2014

YEAR: 2014     DOI: 10.1002/jgra.v119.910.1002/2014JA020161

Chorus; ELF/VLF; Radiation belts; subauroral latitudes; wave-particle interactions

Magnetopause structure favorable for radiation belt electron loss

Magnetopause shadowing is regarded as one of the major reasons for the loss of relativistic radiation belt electrons, although this has not yet been fully validated by observations. Previous simulations on this process assumed that all of the electrons encountering the magnetopause are simply lost into the magnetosheath just as ring current ions can be and did not examine details of the particle dynamics across and inside the magnetopause which has a finite thickness. In this paper, we perform test particle orbit calculation ...

Kim, Kyung-Chan; Lee, Dae-Young;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2014

YEAR: 2014     DOI: 10.1002/2014JA019880

magnetopause shadowing; relativistic electron loss; test particle orbit calculation

2013

Discovery of the action of a geophysical synchrotron in the Earth\textquoterights Van Allen radiation belts

Although the Earth\textquoterights Van Allen radiation belts were discovered over 50 years ago, the dominant processes responsible for relativistic electron acceleration, transport and loss remain poorly understood. Here we show evidence for the action of coherent acceleration due to resonance with ultra-low frequency waves on a planetary scale. Data from the CRRES probe, and from the recently launched multi-satellite NASA Van Allen Probes mission, with supporting modeling, collectively show coherent ultra-low frequency inte ...

Mann, Ian; Lee, E.; Claudepierre, S.; Fennell, J.; Degeling, A.; Rae, I.; Baker, D.; Reeves, G.; Spence, H.; Ozeke, L.; Rankin, R.; Milling, D.; Kale, A.; Friedel, R.; Honary, F.;

Published by: Nature Communications      Published on: 11/2013

YEAR: 2013     DOI: 10.1038/ncomms3795

Van Allen Probes

A novel technique for rapid L* calculation: algorithm and implementation

Computing the magnetic drift invariant, L*, rapidly and accurately has always been a challenge to magnetospheric modelers, especially given the im- portance of this quantity in the radiation belt community. Min et al. (2013) proposed a new method of calculating L* using the principle of energy con- servation. Continuing with the approach outlined therein, the present pa- per focuses on the technical details of the algorithm to outline the implemen- tation, systematic analysis of accuracy, and verification of the speed of the ...

Min, Kyungguk; Bortnik, J.; Lee, Jeongwoo;

Published by: Journal of Geophysical Research      Published on: 05/2013

YEAR: 2013     DOI: 10.1002/jgra.50250

calculating L*; rapid L* calculation; RBSP; Van Allen Probes

Characteristic dimension of electromagnetic ion cyclotron wave activity in the magnetosphere

[1] In this paper, we estimate the size of coherent activity of electromagnetic ion cyclotron (EMIC) waves using the multi-spacecraft observations made during the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission. We calculate the cross-correlations between EMIC wave powers measured by different THEMIS spacecraft, plot them over the separation distances between pairs of observing spacecraft, and determine the 1/e folding distance of the correlations as the characteristic dimension of the co ...

Lee, Jeongwoo; Min, Kyungguk; Kim, Kap-Sung;

Published by: Journal of Geophysical Research: Space Physics      Published on: 04/2013

YEAR: 2013     DOI: 10.1002/jgra.50242

EMIC wave powers; RBSP; THEMIS; Van Allen Probes

A novel technique for rapid L* calculation using UBK coordinates

[1] The magnetic drift invariant (L*) is an important quantity used for tracking and organizing particle dynamics in the radiation belts, but its accurate calculation has been computationally expensive in the past, thus making it difficult to employ this quantity in real-time space weather applications. In this paper, we propose a new, efficient method to calculate L* using the principle of energy conservation. This method uses Whipple\textquoterights (U, B, K) coordinates to quickly and accurately determine trajectories of ...

Min, Kyungguk; Bortnik, J.; Lee, Jeongwoo;

Published by: Journal of Geophysical Research      Published on: 01/2013

YEAR: 2013     DOI: 10.1029/2012JA018177

Generalized L value; L star; RBSP; Van Allen Probes

2012

Global distribution of EMIC waves derived from THEMIS observations

[1] Electromagnetic ion cyclotron (EMIC) waves play an important role in magnetospheric dynamics and their global distribution has been of great interest. This paper presents the distribution of EMIC waves over a broader range than ever before, as enabled by observations with the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft from 2007 to 2010. Our major findings are: (1) There are two major peaks in the EMIC wave occurrence probability. One is at dusk and 8\textendash12 RE where the ...

Min, Kyungguk; Lee, Jeongwoo; Keika, Kunihiro; Li, W.;

Published by: Journal of Geophysical Research      Published on: 05/2012

YEAR: 2012     DOI: 10.1029/2012JA017515

EMIC wave occurrence; EMIC waves; plasma waves; RBSP; Van Allen Probes

2010

Chorus wave generation near the dawnside magnetopause due to drift shell splitting of substorm-injected electrons

We study the relationship between the electron injection and the chorus waves during a substorm event on 23 March 2007. The chorus waves were detected at high geomagnetic latitude (\~70\textdegreeS) Antarctic observatories in the range of 0600\textendash0900 h in magnetic local time (MLT). Electrons drifting from the injection event were measured by two LANL spacecraft at 0300 and 0900 MLT. The mapping of auroral brightening areas to the magnetic equator shows that the injection occurred in an MLT range of 2200\textendash240 ...

Min, Kyungguk; Lee, Jeongwoo; Keika, Kunihiro;

Published by: American Geophysical Union      Published on: 10/2010

YEAR: 2010     DOI: 10.1029/2010JA015474

chorus and substorm; electron drift; RBSP; Substorm Injections; Van Allen Probes



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