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Inner Magnetospheric Response to the Interplanetary Magnetic Field B y Component: Van Allen Probes and Arase Observations
Author(s) -
Case N. A.,
Hartley D. P.,
Grocott A.,
Miyoshi Y.,
Matsuoka A.,
Imajo S.,
Kurita S.,
Shinohara I.,
Teramoto M.
Publication year - 2021
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2020ja028765
Subject(s) - magnetosphere , physics , interplanetary magnetic field , magnetic field , solar wind , geosynchronous orbit , l shell , astrophysics , earth's magnetic field , geophysics , computational physics , astronomy , satellite , quantum mechanics
We utilize 17 years of combined Van Allen Probes and Arase data to statistically analyze the response of the inner magnetosphere to the orientation of the interplanetary magnetic field (IMF) B y component. Past studies have demonstrated that the IMF B y component introduces a similarly oriented B y component into the magnetosphere. However, these studies have tended to focus on field lines in the magnetotail only reaching as close to the Earth as the geosynchronous orbit. By exploiting data from these inner magnetospheric spacecraft, we have been able to investigate the response at radial distances of <7 R E . When subtracting the background magnetic field values, provided by the T01 and IGRF magnetic field models, we find that the IMF B y component does affect the configuration of the magnetic field lines in the inner magnetosphere. This control is observed throughout the inner magnetosphere, across both hemispheres, all radial distances, and all magnetic local time sectors. The ratio of IMF B y to the observed B y residual, also known as the “penetration efficiency,” is found to be ∼0.33. The IMF B z component is found to increase, or inhibit, this control depending upon its orientation.