Radiation belt electron acceleration by chorus waves during the 17 March 2013 storm

• Published in: Journal of geophysical research. Space physics 2014-06, Vol.119 (6), p.4681-4693
• Main Authors: Li, W., Thorne, R. M., Ma, Q., Ni, B., Bortnik, J., Baker, D. N., Spence, H. E., Reeves, G. D., Kanekal, S. G., Green, J. C., Kletzing, C. A., Kurth, W. S., Hospodarsky, G. B., Blake, J. B., Fennell, J. F., Claudepierre, S. G.
• Format: Article
• Language: English
• Subjects: Astrophysics; Chorus waves; Electron acceleration; Electrons; Evolution; local acceleration; Low altitude; Outer radiation belt; peak in PSD; Pitch (inclination); POES satellites; Radiation; Relativism; Satellites; Simulation; Space density; Storms; Waves
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1002/2014JA019945

Local acceleration driven by whistler‐mode chorus waves is fundamentally important for accelerating seed electron populations to highly relativistic energies in the outer radiation belt. In this study, we quantitatively evaluate chorus‐driven electron acceleration during the 17 March 2013 storm, when the Van Allen Probes observed very rapid electron acceleration up to several MeV within ~12 hours. A clear radial peak in electron phase space density (PSD) observed near L* ~4 indicates that an internal local acceleration process was operating. We construct the global distribution of chorus wave intensity from the low‐altitude electron measurements made by multiple Polar Orbiting Environmental Satellites (POES) satellites over a broad region, which is ultimately used to simulate the radiation belt electron dynamics driven by chorus waves. Our simulation results show remarkable agreement in magnitude, timing, energy dependence, and pitch angle distribution with the observed electron PSD near its peak location. However, radial diffusion and other loss processes may be required to explain the differences between the observation and simulation at other locations away from the PSD peak. Our simulation results, together with previous studies, suggest that local acceleration by chorus waves is a robust and ubiquitous process and plays a critical role in accelerating injected seed electrons with convective energies (~100 keV) to highly relativistic energies (several MeV). Key Points Rapid electron acceleration with a radial PSD peak is observed during a storm Chorus driven electron acceleration reproduces observed electron evolution Local acceleration by chorus waves is a robust and ubiquitous process