It has been widely accepted that chorus-driven resonant interaction is an important mechanism responsible for the phase space density (PSD) evolution of electrons in the radiation belt. Recently, a research group from Space Environment Prediction Center (SEPC), affiliated to National Space Science Center (NSSC) presented a quantitative analysis of the effect of the seed electron injection on the evolution of the radiation belt electrons via quasi-linear theory.
Seed electrons, which transport towards the earth from the magnetotail during substorms, are an important source of energetic electrons in radiation belt.
Applying the hybrid finite difference method, YAN Qi and his supervisor from SEPC, Dr. LIU Siqing and Dr. SHI Liqin solved the Fokker-Planck equation and studied the effect of seed electron injection on acceleration of radiation belt electrons driven by chorus waves.
Based on simulation, the results suggest that in the absence of injection, the electrons can be accelerated by chorus waves at large pitch angles, which produced enhancements in the PSD of electrons by a factor of 100-1000 within 1-2 days; while in the presence of injection, chorus waves yield increase in PSD of electrons by accelerating the injected seed electrons.
The study suggests that the injected seed electrons play an important role in the evolution of the radiation belt electrons, therefore may have certain potential value on the prediction of energetic electron flux of radiation belt during substroms.
The study is published on Science China Technological Sciences, doi: 10.1007/s11431-01205078-0. (Full text).
For more information on SEPC, please visit http://eng.sepc.ac.cn/index.php.
Space Environment Prediction Center, National Space Science Center