JpGU-AGU Joint Meeting 2017

Presentation information

[EE] Oral

P (Space and Planetary Sciences) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM16] [EE] Physics of Inner Magnetosphere Coupling

Wed. May 24, 2017 9:00 AM - 10:30 AM A02 (Tokyo Bay Makuhari Hall)

convener:Danny Summers(Memorial University of Newfoundland), Jichun Zhang(University of New Hampshire Main Campus), Yusuke Ebihara(Research Institute for Sustainable Humanosphere, Kyoto University), Kunihiro Keika(Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo ), Aleksandr Y Ukhorskiy(Johns Hopkins University Applied Physics Laboratory), Dae-Young Lee(Chungbuk Natl Univ), Yiqun Yu(Beihang University), Yoshizumi Miyoshi(Institute for Space-Earth Environmental Research, Nagoya University), Chairperson:Jichun Zhang(University of New Hampshire Main Campus)

9:30 AM - 9:45 AM

[PEM16-21] Landau Resonance Acceleration of MeV Electrons by Obliquely Propagating Whistler-mode Chorus Emissions

*Yoshiharu Omura1, Yikai HSIEH1, John C Foster2, Philip J Erickson2, Craig A Kletzing3, Daniel N Baker4 (1.Reserach Institute for Sustainable Humanosphere, Kyoto University, 2.Haystack Observatory, Massachusetts Institute of Technology, 3.Department of Physics and Astronomy, University of Iowa, 4.Laboratory for Atmospheric and Space Physics, University of Colorado)

Keywords:wave-particle interaction, radiation belts, particle acceleration

A recent analysis of wave and particle data obtained by the Van Allen Probes [Foster et al., 2017] demonstrates highly efficient acceleration of relativistic electrons by whistler-mode chorus emissions. The analysis identified that the acceleration is mostly due to the cyclotron resonance of relativistic electrons with chorus emissions propagating quasi-parallel to the ambient magnetic field. As the energy of an electron becomes relativistic (1 - 2 MeV), the parallel resonance velocity approaches zero near the equator, where nonlinear trapping of resonant electrons becomes possible, resulting in relativistic turning acceleration [Omura et al., 2007]. The detailed subpacket analysis shows that there arises a parallel wave electric field that can trap energetic electrons through Landau resonance. A recent test particle simulation [Hsieh and Omura, 2017], however, shows that the perpendicular wave electric field can also play a significant role in trapping and accelerating relativistic electrons through Landau resonance. We present a theoretical analysis of the Landau resonance acceleration, and verify it by the subpacket analysis of chorus emissions observed by Van Allen Probes. We compare the efficiencies of accelerations by the cyclotron resonance and the Landau resonance.

[1] Foster, J. C., P. J. Erickson, Y. Omura, D. N. Baker, C. A. Kletzing, S. G. Claudepierre, Van Allen Probes Observations of Prompt MeV Radiation Belt Electron Acceleration in Non-Linear Interactions with VLF Chorus, J. Geophy. Res. Space Physics, doi: 10.1002/2016JA023429, 2017.
[2] Omura, Y., N. Furuya, D. Summers, Relativistic turning acceleration of resonant electrons by coherent whistler-mode waves in a dipole magnetic field, J. Geophys. Res., Vol. 112, A06236, doi:10.1029/2006JA012243, 2007.
[3] Hsieh, Y.-K, and Y. Omura, Nonlinear dynamics of electrons interacting with oblique whistler-mode chorus in the magnetosphere, J. Geophys. Res. Space Physics, 10.1002/2016JA022891, 2017.