Analysis of the Behavior of the Solar Wind Ion Flux in the Region of the Interplanetary Shock Overshoot

The structure of the solar wind plasma flow downstream of the ramp of the interplanetary shock is studied based on the BMSW plasma spectrometer installed onboard the SPEKTR-R spacecraft. Particular attention is paid to the overshoot region, where correlated oscillations of the ion flux and magnetic field, which decaying with distance from the ramp, are observed. They are formed by two populations of ions: the inflowing solar wind and the beam of reflected ions. Based on an analysis of 26 crossings of interplanetary shock fronts, in which overshoots were observed in the value of the ion flux and the magnetic field, it is shown that overshoots form not only in supercritical shock, but also in those with Mach numbers that are less than or approach the value of the first critical Mach number. It is found that the formation and value of the overshoot amplitude in the structure of the shock front are significantly influenced by the angle between the normal to the shock front and the magnetic field vector ahead of the front, the Mach number, and the magnetic and plasma compression at the wave front. It is established that the oscillation wavelength determined from the magnetic field measurements onboard the WIND spacecraft, on average, coincides with the oscillation wavelength determined from the ion flux on the SPEKTR-R spacecraft, while the spatial scales of the oscillation-damping regions can greatly differ.