Inner Magnetospheric Response to the Interplanetary Magnetic Field By Component: Van Allen Probes and Arase Observations. Issue 1 (5th January 2021)

• Record Type: Journal Article
• Authors: Case, N. A.; Hartley, D. P.; Grocott, A.; Miyoshi, Y.; Matsuoka, A.; Imajo, S.; Kurita, S.; Shinohara, I.; Teramoto, M.
• Is Part Of: Journal of geophysical research. Volume 126:Issue 1(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-01-05
• Subjects: By -- y‐component -- inner magnetosphere -- IMF -- response; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2020JA028765
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: 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. Key Points: The influence of interplanetary magnetic field (IMF) B y is observed throughout the inner magnetosphere, using Van Allen Probes and Arase observations The median ratio of change in the observed B y to IMF B y is ∼0.33, though a clock angle dependence is found We find a consistent effect across both hemispheres, all magnetic local time sectors, and all radial distances