Change of Spectral Properties of Magnetic Field Fluctuations across Different Types of Interplanetary Shocks

Abstract

Abstract The interaction between interplanetary (IP) shocks and the solar wind has been studied in the past for the understanding of energy dissipation mechanisms within collisionless plasmas. Compared to the study of fast shocks, other types of IP shocks, including slow mode shocks (i.e., fast forward, fast reverse, slow forward, and slow reverse shocks) remained largely unnoticed. We analyze magnetic field fluctuations observed by the Wind spacecraft from 1995 to 2021 upstream and downstream of the IP shocks using a continuous wavelet transform. The evolution of spectral indices in the ion inertial and transition ranges and the changes in distributions of characteristic ion length scales with respect to the spectral break and proton beta are presented. We found that spectral indices in both inertial and transition ranges and the characteristic length scale distributions are statistically conserved across three types of IP shocks, suggesting that mechanisms associated with the energy dissipation are unaffected by the shocks. The results obtained for the transition range of fast reverse shocks show a larger difference between upstream and downstream plasmas and this will be further studied.