Multispacecraft study of interplanetary shocks at 1 AU.

Abstract:

Interplanetary (IP) shocks propagate through the heliosphere perturbing the solar wind plasma. They can be driven by Interplanetary Coronal Mass Ejections (ICMEs) and Stream Interaction Regions (SIRs). They play an active role in the acceleration of ions to suprathermal energies. Shock fronts evolve as they move from the Sun. Their surfaces can be far from uniform and be modulated by changes in the solar wind (magnetic field orientation, flow velocity), and perturbations upstream and downstream from the shocks, i.e., electromagnetic waves. In this work we use multispacecraft data (STEREO, WIND, ACE) to study shock characteristics at different helio-longitudes and determine the properties of the waves near them. We also determine shock longitudinal extensions and foreshock sizes. The variations of geometry along the shock surface can result in different extensions of the wave and ion foreshocks ahead of the shocks, and in different wave modes upstream and downtream of the shocks. Thus, the region with modified solar wind ahead of the shocks can be very asymmetric.