TY  - JOUR
A1  - Ripoll, Jean-Francois
A1  - Loridan, Vivien
A1  - Denton, Michael H.
A1  - Cunningham, Gregory
A1  - Reeves, G.
A1  - Santolik, O.
A1  - Fennell, Joseph
A1  - Turner, Drew L.
A1  - Drozdov, Alexander
A1  - Villa, Juan Sebastian Cervantes
A1  - Shprits, Yuri Y.
A1  - Thaller, Scott A.
A1  - Kurth, William S.
A1  - Kletzing, Craig A.
A1  - Henderson, Michael  G.
A1  - Ukhorskiy, Aleksandr Y.
T1  - Observations and Fokker-Planck Simulations of the L-Shell, Energy, and Times
JF  - Journal of geophysical research : Space physics
N2  - The evolution of the radiation belts in L-shell (L), energy (E), and equatorial pitch angle (alpha(0)) is analyzed during the calm 11-day interval (4-15 March) following the 1 March 2013 storm. 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, alpha(0)) regions persist through 11 days of hiss wave scattering; the pitch angle-dependent inner belt core (L similar to <2.2 and E < 700 keV), pitch angle homogeneous outer belt low-energy core (L > similar to 5 and E similar to < 100 keV), and a distinct pocket of electrons (L similar to [4.5, 5.5] and E similar to [0.7, 2] MeV). The pitch angle homogeneous outer belt is explained by the diffusion coefficients that are roughly constant for alpha(0) similar to <60 degrees, E > 100 keV, 3.5 < L < L-pp similar to 6. Thus, observed unidirectional flux decays can be used to estimate local pitch angle diffusion rates in that region. Top-hat distributions are computed and observed at L similar to 3-3.5 and E = 100-300 keV.
KW  - radiation belts
KW  - wave-particle interactions
KW  - electron lifetime
KW  - pitch angle diffusion coefficient
KW  - hiss waves
Y1  - 2018
U6  - https://doi.org/10.1029/2018JA026111
SN  - 2169-9380
SN  - 2169-9402
VL  - 124
IS  - 2
SP  - 1125
EP  - 1142
PB  - American Geophysical Union
CY  - Washington
ER  - 
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  -