Premium
Wave Normal Angle Distribution of Fast Magnetosonic Waves: A Survey of Van Allen Probes EMFISIS Observations
Author(s) -
Zou Zhengyang,
Zuo Pingbing,
Ni Binbin,
Wei Fengsi,
Zhao Zhengyu,
Cao Xing,
Fu Song,
Gu Xudong
Publication year - 2019
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2019ja026556
Subject(s) - van allen radiation belt , van allen probes , physics , earth's magnetic field , geomagnetic latitude , latitude , magnetosphere , equator , computational physics , geophysics , magnetic field , geodesy , geology , astronomy , quantum mechanics
Using Van Allen Probe Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) wave observations from September 2012 to May 2018, we statistically investigate the distributions of power‐weighted wave normal angle (WNA) of fast magnetosonic (MS) waves from L = 2–6 within ±15° geomagnetic latitudes. The spatial distributions show that the MS WNAs are mainly confined within 87 – 89° near the geomagnetic equator and decrease with increasing magnetic latitude. Further quantitative investigation demonstrates that the WNAs normally distribute as a mixture of two Gaussian distributions ranging from 85° to 88°, and the tangent of it can decrease as a Kappa distribution function when the waves propagate to higher latitudes. Our study completes the survey of spatial distributions of MS WNAs and provides quantitative dependence of the WNA distribution on the magnetic latitude in the inner magnetosphere, which can be readily useful in future global simulations of radiation belt particle dynamics.