Authors: G.J. Fowler, C.T. Russell; J. Raeder
Affiliation: University of California, Los Angeles, Institute of Geophysics
and Planetary Physics; University of New Hampshire
It is well known that dynamic pressure changes in the solar wind determine changes in the Earth's magnetic field. However, the magnetopsheric response is not as rapid as the abrupt changes associated with a thin interplanetary shock front. We use an MHD model to investigate the rise time of sudden impulses (SIs) observed by the Polar spacecraft. By increasing the solar wind speed we see the magnetosphere respond to the compression more rapidly, and vice versa decreasing the speed of the shock will prolong the magnetospheric response. Previous investigations with the T89 and T96 models have shown that at high altitudes on the dayside magnetospheric compression can lead to decreases in the magnetic field magnitude. Simulations with the MHD model predict similar responses, which is consistent with observations.