Bounce averaged diffusion coefficients in a physics based magnetic field geometry from RAM-SCB

Thursday, 18 December 2014
Lei Zhao1, Yiqun Yu2, Gian Luca Delzanno2 and Vania Jordanova2, (1)Los Alamos National Lab, Los Alamos, NM, United States, (2)Los Alamos National Laboratory, Los Alamos, NM, United States
Local acceleration via whistler wave and particle interaction plays an important role in particle dynamics in the radiation belt. In this work we explore wave-particle interaction in different magnetic field configurations related to the 17 March, 2013 storm. We consider the Earth's magnetic dipole field as a reference, and compare the results against non-dipole field configurations corresponding to quiet and stormy conditions. The latter are obtained with RAM-SCB, a code that models the Earth's ring current and provides a realistic modeling of the Earth's magnetic field. By applying quasi-linear theory, the bounce-averaged electron pitch angle, energy and mixed term diffusion coefficients are calculated for each magnetic field configuration. It is shown that the magnetic field can have a significant influence on the diffusion coefficients via the wave-particle resonance condition. In addition, the equatorial pitch angle, wave frequency and spectral distribution of whistler waves also affect the bounce-averaged diffusion coefficients in particle energy range from KeV to MeV. Part of the ongoing work will focus on the phase space density evolution based on the Fokker-Planck equation with the bounce-averaged diffusion coefficients previously calculated.