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Relativistic electron's butterfly pitch angle distribution modulated by localized background magnetic field perturbation driven by hot ring current ions
Author(s) -
Xiong Ying,
Chen Lunjin,
Xie Lun,
Fu Suiyan,
Xia Zhiyang,
Pu Zuyin
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl072558
Subject(s) - pitch angle , physics , electron , ring current , magnetic field , magnetosphere , van allen radiation belt , atomic physics , ion , electric field , butterfly , perturbation (astronomy) , computational physics , geophysics , nuclear physics , finance , quantum mechanics , economics
Dayside modulated relativistic electron's butterfly pitch angle distributions (PADs) from ∼200 keV to 2.6 MeV were observed by Van Allen Probe B at L = 5.3 on 15 November 2013. They were associated with localized magnetic dip driven by hot ring current ion (60–100 keV proton and 60–200 keV helium and oxygen) injections. We reproduce the electron's butterfly PADs at satellite's location using test particle simulation. The simulation results illustrate that a negative radial flux gradient contributes primarily to the formation of the modulated electron's butterfly PADs through inward transport due to the inductive electric field, while deceleration due to the inductive electric field and pitch angle change also makes in part contribution. We suggest that localized magnetic field perturbation, which is a frequent phenomenon in the magnetosphere during magnetic disturbances, is of great importance for creating electron's butterfly PADs in the Earth's radiation belts.