Solar Wind Energy Budget Dilemma During Substorms Induced by Interplanetary Shocks

Abstract

AbstractInterplanetary (IP) shocks can trigger substorms when they interact the magnetosphere. In study of Hajra and Tsurutani (2018, https://doi.org/10.1016/0032-0633(77)90001-0), they reported a shock‐induced substorm event where the energy dissipation exceeded the energy input ( parameter). In this study, we examined 198 IP shock‐induced substorms from 1995 to 2021 and found 32 underpowered events where the energy dissipation exceeded the energy input calculated from IP shock sheath parameters. We also found underpowered events using other newly developed energy functions. To resolve this dilemma, we introduce the concept of dual compressions of the interplanetary magnetic field by both the IP shock and the bow shock, respectively. Based on in situ observations in the magnetosheath, we obtained a set of new parameters from the dual compressions. The stronger magnetic field resulting from the double compressions reconnects the geomagnetic field, leading to an increased input of energy into the magnetosphere. This new energy input is generally sufficient to balance the energy dissipation.