Electron Density Images of the Middle and High Latitude Magnetosphere in Response to the Solar Wind

Electron density images and plasma dynamics in the middle and high latitude dayside magnetosphere are studied with the IMAGE/RPI remote measurements of the electron densities along magnetic field lines, measured before and during a magnetic storm when the solar wind and interplanetary magnetic field (IMF) impinging on the magnetopause varied considerably. Several regions of different density distribution characteristics, including plasmasphere, plasma trough, sub-auroral/auroral density depletion, density enhancements in the aurora/cusp, and polar cap, are identified in 'two dimensional images', i.e., along the satellite orbit and field lines. The plasma dynamics, such as the plasma refilling in the outer plasmasphere and the plasma acceleration in the aurora/cusp region are inferred from density gradients along the field lines. It is shown that the densities and locations of the plasma regions vary in accordance with the solar wind, particularly with the IMF variations for the case examined. The changes in these regions reflect the way the magnetosphere reconfigures in response to changes in the solar wind.