TY  - JOUR
A1  - Drozdov, Alexander
A1  - Shprits, Yuri Y.
A1  - Usanova, Maria E.
A1  - Aseev, Nikita
A1  - Kellerman, Adam C.
A1  - Zhu, H.
T1  - EMIC wave parameterization in the long-term VERB code simulation
JF  - Journal of geophysical research : Space physics
N2  - Electromagnetic ion cyclotron (EMIC) waves play an important role in the dynamics of ultrarelativistic electron population in the radiation belts. However, as EMIC waves are very sporadic, developing a parameterization of such wave properties is a challenging task. Currently, there are no dynamic, activity-dependent models of EMIC waves that can be used in the long-term (several months) simulations, which makes the quantitative modeling of the radiation belt dynamics incomplete. In this study, we investigate Kp, Dst, and AE indices, solar wind speed, and dynamic pressure as possible parameters of EMIC wave presence. The EMIC waves are included in the long-term simulations (1year, including different geomagnetic activity) performed with the Versatile Electron Radiation Belt code, and we compare results of the simulation with the Van Allen Probes observations. The comparison shows that modeling with EMIC waves, parameterized by solar wind dynamic pressure, provides a better agreement with the observations among considered parameterizations. The simulation with EMIC waves improves the dynamics of ultrarelativistic fluxes and reproduces the formation of the local minimum in the phase space density profiles.
KW  - radiation belts
KW  - VERB code
KW  - EMIC
Y1  - 2017
U6  - https://doi.org/10.1002/2017JA024389
SN  - 2169-9380
SN  - 2169-9402
VL  - 122
SP  - 8488
EP  - 8501
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Aseev, Nikita
A1  - Shprits, Yuri Y.
A1  - Drozdov, Alexander
A1  - Kellerman, Adam C.
A1  - Usanova, Maria E.
A1  - Wang, D.
A1  - Zhelavskaya, Irina
T1  - Signatures of Ultrarelativistic Electron Loss in the Heart of the Outer Radiation Belt Measured by Van Allen Probes
JF  - Journal of geophysical research : Space physics
N2  - Up until recently, signatures of the ultrarelativistic electron loss driven by electromagnetic ion cyclotron (EMIC) waves in the Earth's outer radiation belt have been limited to direct or indirect measurements of electron precipitation or the narrowing of normalized pitch angle distributions in the heart of the belt. In this study, we demonstrate additional observational evidence of ultrarelativistic electron loss that can be driven by resonant interaction with EMIC waves. We analyzed the profiles derived from Van Allen Probe particle data as a function of time and three adiabatic invariants between 9 October and 29 November 2012. New local minimums in the profiles are accompanied by the narrowing of normalized pitch angle distributions and ground‐based detection of EMIC waves. Such a correlation may be indicative of ultrarelativistic electron precipitation into the Earth's atmosphere caused by resonance with EMIC waves.
Y1  - 2017
U6  - https://doi.org/10.1002/2017JA024485
SN  - 2169-9380
SN  - 2169-9402
VL  - 122
SP  - 10102
EP  - 10111
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Shprits, Yuri Y.
A1  - Kellerman, Adam C .
A1  - Aseev, Nikita
A1  - Drozdov, Alexander
A1  - Michaelis, Ingo
T1  - Multi-MeV electron loss in the heart of the radiation belts
JF  - Geophysical research letters
N2  - Significant progress has been made in recent years in understanding acceleration mechanisms in the Earth's radiation belts. In particular, a number of studies demonstrated the importance of the local acceleration by analyzing the radial profiles of phase space density (PSD) and observing building up peaks in PSD. In this study, we focus on understanding of the local loss using very similar tools. The profiles of PSD for various values of the first adiabatic invariants during the previously studied 17 January 2013 storm are presented and discussed. The profiles of PSD show clear deepening minimums consistent with the scattering by electromagnetic ion cyclotron waves. Long-term evolution shows that local minimums in PSD can persist for relatively long times. During considered interval of time the deepening minimums were observed around L* = 4 during 17 January 2013 storm and around L* = 3.5 during 1 March 2013 storm. This study shows a new method that can help identify the location, magnitude, and time of the local loss and will help quantify local loss in the future. This study also provides additional clear and definitive evidence that local loss plays a major role for the dynamics of the multi-MeV electrons.
Y1  - 2017
U6  - https://doi.org/10.1002/2016GL072258
SN  - 0094-8276
SN  - 1944-8007
VL  - 44
IS  - 3
SP  - 1204
EP  - 1209
PB  - American Geophysical Union
CY  - Washington
ER  -