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)

10:15 AM - 10:30 AM

[PEM16-24] Energetic ring current proton spectra measured by the Van Allen Probes

*Danny Summers1, Run Shi2 (1.Memorial University of Newfoundland, 2.Wuhan University)

Keywords:ring current protons, extreme proton spectra, Van Allen Probes

We examine two geomagnetic storm periods,namely March 17-20,2013 and March 17-20,2015,and analyze proton spectra measured by the Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) on board the Van Allen Probes. In particular,we consider the most intense proton spectra over the energy range 50 - 600 keV ,for outer-zone L-shells, during these storm periods. Recent theory has been developed to model the limitation of energetic ring current ion spectra resulting from the action of pitch-angle scattering by electromagnetic ion cyclotron (EMIC) waves. The theory suggests that a limiting (extreme) spectrum is achieved when the EMIC waves acquire a certain gain over a given convective length scale for all frequencies over which wave growth occurs. We obtain the theoretical limiting spectrum numerically, and also show that the limiting spectrum varies as 1/E for large kinetic energy E. Comparison of the observed extreme proton spectra with the corresponding numerical limiting spectra provides evidence that the extreme spectra are controlled by EMIC wave scattering.