Publication Date:
2019
Description:
Abstract
Using Van Allen Probe 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 ±15o geomagnetic latitudes. The spatial distributions show that the MS WNAs are mainly confined within 87o ‐ 89o 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 85o to 88o 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 wave normal angle distribution on the magnetic latitude in the inner magnetosphere, which can be readily useful in future global simulations of radiation belt particle dynamics.
Print ISSN:
2169-9380
Electronic ISSN:
2169-9402
Topics:
Geosciences
,
Physics