Study of Interplanetary Shocks Using Multi-Spacecraft Observations

We investigate the characteristics of interplanetary (IP) shock waves associated with a stream interaction region (SIR) observed during April 21–24, 2007 by STEREO‐A/B, WIND and ACE spacecraft. During the years 2007–2008 STEREO‐A observed 43 and STEREO‐B crossed 41 shocks. As IP shocks propagate, they encounter solar wind with different characteristics (density, speed) and different orientations of the ambient magnetic field. Hence, it is expected that shock profiles will vary strongly through the space. We use magnetic field and plasma data to study shock structure, strength and orientation. In this example of a SIR we find that the characteristics of the shocks change dramatically from one region to another, the shock structure can be quasi‐perpendicular as observed in one spacecraft and quasi‐parallel when crossed at other point. Low frequency waves with different characteristics appear upstream and downstream of forward and reverse shocks. In this example the region upstream of the forward quasi‐perpe...