Interaction of an interplanetary shock with the heliospheric plasma sheet

The interaction of an interplanetary shock with the heliospheric plasma sheet (HPS) is simulated using the 2 12D MHD model in the meridional plane. The shock structure is generated by a velocity pulse and consists of a strong broad forward shock (FS) with a concave shape and a much weaker and narrower reverse shock (RS) with a convex shape. The flat equatorial HPS, with its larger mass density and slower flow velocity, modifies this shock structure. A dimple is formed at the FS and a reverse dimple is formed at the RS. A large distortion of the heliospheric current sheet (HCS) occurs when the velocity pulse is introduced outside the HPS. The interaction of a shock with the HPS leads to very large southward values of the interplanetary magnetic field due to an effect of shock compression, field-line draping, and deflection of the HCS.