Nonlinear Magnetosphere-Ionosphere Coupling in Near-Earth Space via Closure of the Partial Ring Current

Presenter Information

Michael W. Liemohn, University of MichiganFollow
R. M. Katus, University of Michigan
L. K. Smith, University of Michigan
R. M. Skoug, Los Alamos National Laboratory
J. Niehof, Los Alamos National Laboratory
C. W. Smith, University of New Hampshire
J. R. Wygant, University of Minnesota
R. Ilie, University of Michigan
N. Y. Ganushkina, University of Michigan

Location

Yosemite National Park

Start Date

2-11-2014 5:40 PM

End Date

2-11-2014 5:55 PM

Description

Localized potential electric field modification is identified in the Van Allen Probes data during magnetic storm times, when significant energetic plasma (above a keV) is injected into the inner magnetosphere. This modification is from the closure of field-aligned currents through the ionosphere in a region of low conductance just equatorward of the auroral oval. Observations from the Van Allen Probe instruments HOPE, RBSPICE, EMFISIS, and EFW are presented for several magnetic storms, showing the relationship of the plasma pressure peak and the magnetic field distortion to the local electric field vector. An assessment of the intensity of the nonlinear feedback on the electric field is made by determining its deviation from the large-scale potential electric field, as observed by EFW outside of the pressure peak. The coupling that emerges is in agreement with numerical simulations of near-Earth space that predict strong perturbation of the local electric field near pressure peaks.

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