SM23A-2530
Field Aligned Currents Derived from Pressure Profiles Obtained from TWINS ENA Images
Tuesday, 15 December 2015
Poster Hall (Moscone South)
Keith Wood1, J D Perez1, David J McComas2, Jerry Goldstein2 and Philip W Valek3, (1)Auburn University, Physics Department, Auburn, AL, United States, (2)Southwest Research Institute, San Antonio, TX, United States, (3)Southwest Research Inst, San Antonio, TX, United States
Abstract:
Field aligned currents (FACs) that flow from the Earth’s magnetosphere into the ionosphere are an important coupling mechanism in the interaction of the solar wind with the Earth’s magnetosphere. Assuming pressure balance along with charge conservation yields an expression for the FACs in terms of plasma pressure gradients and pressure anisotropy. The Two Wide-Angle Imaging Neutral Atom Spectrometers (TWINS) mission, the first stereoscopic ENA magnetospheric imager, provides global images of the inner magnetosphere from which ion pressure distributions and pressure anisotropies can be obtained. Following the formulations in Heineman [1990] and using results from TWINS observations, we calculate the distribution of field aligned currents for the 17-18 March 2015 geomagnetic storm in which extended ionospheric precipitation was observed. Initial results for the field aligned currents will be generated assuming an isotropic pitch angle distribution. Global maps of field aligned currents during the main and recovery phase of the storm will be presented.
Heinemann, H. (1990), Representations of Currents and Magnetic Fields in Anisotropic Magnetohydrostatic Plasma, J. Geophys. Res., 95, 7789.
