Wave Normal Angle Distribution of Fast Magnetosonic Waves: A Survey of Van Allen Probes EMFISIS Observations. Issue 7 (30th July 2019)

• Record Type: Journal Article
• Authors: Zou, Zhengyang; Zuo, Pingbing; Ni, Binbin; Wei, Fengsi; Zhao, Zhengyu; Cao, Xing; Fu, Song; Gu, Xudong
• Is Part Of: Journal of geophysical research. Volume 124:Issue 7(2019)
• Page Start: 5663
• Page End: 5674
• Publication Date: 2019-07-30
• Subjects: fast magnetosonic waves -- power‐weighted wave normal angles -- spatial distributions -- latitudinal dependence -- empirical model; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2019JA026556
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: 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. Key Points: Power‐weighted wave normal angles (WNAs) of fast magnetosonic (MS) waves mainly range from 87 – 89° near the geomagnetic equator, ~85° at off‐equatorial region The wave normal angles are distributed as a mixture of two Gaussian distributions, and the tangent of it decreases as a Kappa distribution function with increasing geomagnetic latitude The statistical results provide valuable information for incorporation into future simulations of radiation belt particle dynamics