Multispacecraft measurements of plasma and magnetic field variations in the magnetosheath: Comparison with Spreiter models and motion of the structures

Large (from tens of percent up to several times) ion flux (or density) and magnetic field magnitude variations are typical magnetosheath features. Case and statistical comparisons of simultaneous solar wind observations, magnetosheath observations, and the gasdynamic model for the magnetosheath flow of Spreiter et al. (Planet. Space Sci. 14 (1966) 223) show that two types of magnetosheath plasma and magnetic field variations exist: • e cases, they are a repetition or amplification of solar wind or IMF disturbances which pass through the bow shock; the most cases, these variations are endogenous; i.e., they originate inside the magnetosheath. tence times and/or correlation lengths for the magnetosheath plasma variations were investigated via detailed comparison of simultaneous magnetosheath measurements from several spacecraft. For small separation distances (about 0.5RE) we used the satellite pair INTERBALL-1/MAGION-4; for larger distances (up to 10–30RE on the same or on the opposite flanks of the magnetosheath) we used the INTERBALL-1/GEOTAIL/IMP 8 measurements. e cases, we observed a remarkable coincidence of the magnetosheath plasma behavior from the spacecraft separated by more than 10RE. It seems that the compression plasma structures move tailward together with the magnetosheath plasma flow.