TY  - JOUR
A1  - Aseev, Nikita
A1  - Shprits, Yuri Y.
A1  - Wang, Dedong
A1  - Wygant, John
A1  - Drozdov, Alexander
A1  - Kellerman, Adam C.
A1  - Reeves, Geoffrey D.
T1  - Transport and loss of ring current electrons inside geosynchronous orbit during the 17 March 2013 storm
JF  - Journal of geophysical research : Space physics
N2  - Ring current electrons (1–100 keV) have received significant attention in recent decades, but many questions regarding their major transport and loss mechanisms remain open. In this study, we use the four‐dimensional Versatile Electron Radiation Belt code to model the enhancement of phase space density that occurred during the 17 March 2013 storm. Our model includes global convection, radial diffusion, and scattering into the Earth's atmosphere driven by whistler‐mode hiss and chorus waves. We study the sensitivity of the model to the boundary conditions, global electric field, the electric field associated with subauroral polarization streams, electron loss rates, and radial diffusion coefficients. The results of the code are almost insensitive to the model parameters above 4.5 RERE, which indicates that the general dynamics of the electrons between 4.5 RE and the geostationary orbit can be explained by global convection. We found that the major discrepancies between the model and data can stem from the inaccurate electric field model and uncertainties in lifetimes. We show that additional mechanisms that are responsible for radial transport are required to explain the dynamics of ≥40‐keV electrons, and the inclusion of the radial diffusion rates that are typically assumed in radiation belt studies leads to a better agreement with the data. The overall effect of subauroral polarization streams on the electron phase space density profiles seems to be smaller than the uncertainties in other input parameters. This study is an initial step toward understanding the dynamics of these particles inside the geostationary orbit.
KW  - ring current electrons
KW  - magnetospheric convection
KW  - ensemble modeling
KW  - inner magnetosphere
KW  - electron transport
KW  - wave-particle interactions
Y1  - 2019
U6  - https://doi.org/10.1029/2018JA026031
SN  - 2169-9380
SN  - 2169-9402
VL  - 124
IS  - 2
SP  - 915
EP  - 933
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Wang, Dedong
A1  - Shprits, Yuri Y.
A1  - Zhelayskaya, Irina S.
A1  - Agapitov, Oleksiy
A1  - Drozdov, Alexander
A1  - Aseev, Nikita
T1  - Analytical chorus wave model derived from van Allen Probe Observations
JF  - Journal of geophysical research : Space physics
N2  - Chorus waves play an important role in the dynamic evolution of energetic electrons in the Earth's radiation belts and ring current. Using more than 5 years of Van Allen Probe data, we developed a new analytical model for upper‐band chorus (UBC; 0.5fce < f < fce) and lower‐band chorus (LBC; 0.05fce < f < 0.5fce) waves, where fce is the equatorial electron gyrofrequency. By applying polynomial fits to chorus wave root mean square amplitudes, we developed regression models for LBC and UBC as a function of geomagnetic activity (Kp), L, magnetic latitude (λ), and magnetic local time (MLT). Dependence on Kp is separated from the dependence on λ, L, and MLT as Kp‐scaling law to simplify the calculation of diffusion coefficients and inclusion into particle tracing codes. Frequency models for UBC and LBC are also developed, which depends on MLT and magnetic latitude. This empirical model is valid in all MLTs, magnetic latitude up to 20°, Kp ≤ 6, L‐shell range from 3.5 to 6 for LBC and from 4 to 6 for UBC. The dependence of root mean square amplitudes on L are different for different bands, which implies different energy sources for different wave bands. This analytical chorus wave model is convenient for inclusion in quasi‐linear diffusion calculations of electron scattering rates and particle simulations in the inner magnetosphere, especially for the newly developed four‐dimensional codes, which require significantly improved wave parameterizations.
KW  - chorus waves
KW  - radiation belt electrons
KW  - ring current electrons
KW  - analytical model
KW  - wave-particle interactions
KW  - diffusion coefficients
Y1  - 2019
U6  - https://doi.org/10.1029/2018JA026183
SN  - 2169-9380
SN  - 2169-9402
VL  - 124
IS  - 2
SP  - 1063
EP  - 1084
PB  - American Geophysical Union
CY  - Washington
ER  -