Propagation of Interplanetary Shock and Its Consequent Geoeffectiveness

Abstract

Using 2.5 dimensional ideal magnetohydrodynamic (MHD) equations, the propagation of the interplanetary shock and its consequent geoeffectiveness are studied. The numerical results show that the heliospheric current sheet (HCS)–heliospheric plasma sheet (HPS) structure has some negative influences on the propagation of the interplanetary shock. For the shock propagating aslant the HCS, the segment on the opposite side of HCS with respect to shock nose is weaker than the other segment on the same side. The bending effect of the interplanetary shock on the magnetic field is an important mechanism responsible for the geomagnetic storm. The strength and the direction of the bending effect of shock on the magnetic field highly depend on the local normal (or shape) of the shock front. As a quasi‐parallel shock in the propagating direction of shock nose, the strength of its bending effect is very weak. On the contrary, it belongs to a oblique shock mode on the edge of the shock nose, the strength of the bending effect becomes stronger. A concave is formed at the shock front across the HCS–HPS, at which the bending effect is efficiently intensified. The angular distance Δθp between the Earth and the HCS is found to be an important factor which can remarkably affect the consequent geoeffectiveness. The numerical results suggest that: whatever the direction of the interplanetary shock propagates in, there is no notable geoeffectiveness at the shock nose; For the shock propagating along the HCS, the intensest geoeffectiveness occurs on the edge of HCS‐HPS; in contrast, the region at the opposite side of HCS with respect to the shock nose becomes most geoeffective, when the shock propagates aslant the HCS.

Substorm‐Time Ground dB/dt Variations Controlled by Interplanetary Shock Impact Angles: A Statistical Study

“…When IP shocks strike the Earth's magnetosphere, many geomagnetic perturbations are observed in the magnetosphere-ionosphere (MI) system, including magnetic field perturbations in geosynchronous orbit (Villante & Piersanti, 2011;, ultra-low frequency wave activity (C.-R. Zong et al, 2009), satellite orbital drag (Krauss et al, 2018;, ionospheric disturbances (Belakhovsky et al, 2017;Liu et al, 2023), and sudden impulse signatures observed by ground magnetometers around the world (Chao & Lepping, 1974;Russell et al, 1994;Smith et al, 2020). Therefore, understanding IP shock geoeffectiveness is of paramount importance in space weather investigations (Alves et al, 2011;Echer et al, 2004;Su et al, 2009).…”

“…Wang et al., 2010; Zong et al., 2009), satellite orbital drag (Krauss et al., 2018; Oliveira & Zesta, 2019), ionospheric disturbances (Belakhovsky et al., 2017; Liu et al., 2023), and sudden impulse signatures observed by ground magnetometers around the world (Chao & Lepping, 1974; Russell et al., 1994; Smith et al., 2020). Therefore, understanding IP shock geoeffectiveness is of paramount importance in space weather investigations (Alves et al., 2011; Echer et al., 2004; Su et al., 2009).…”