AUTHOR=Song Xiaojian , Zuo Pingbing , Shen Zhenning , Feng Xueshang , Xu Xiaojun , Wang Yi , Jiang Chaowei , Luo Xi 

TITLE=Overshoot Structure Near the Earth’s Subsolar Magnetopause Generated by Magnetopause Motions

JOURNAL=Frontiers in Physics

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2022.775792

DOI=10.3389/fphy.2022.775792

ISSN=2296-424X

ABSTRACT=For magnetopause crossing events, the observed magnetospheric magnetic fields in the vicinity of the subsolar magnetopause frequently present an overshoot structure, i.e., in small vicinity of the magnetopause, the closer to the magnetopause, the stronger the magnetospheric magnetic field is. In this investigation, an automatic identification algorithm is developed to rapidly and effectively search the magnetopause crossing events using THEMIS data from 2007 to 2021. Nearly 59% of magnetopause crossing events identified near the subsolar region appear the overshoot structure, which may be caused by the redistribution of the magnetospheric magnetic field due to the rapid magnetopause motion. The statistical result shows that, for overshoot cases, the normalized change rate of magnetospheric magnetic field near the magnetopause is linearly related to the normalized magnetopause velocity. This kind of linear relationship can also be derived from an empirical magnetopause model, which verifies the connection between the formation of overshoot and the magnetopause motion.  In addition, the proportionality constant of linear relation is much smaller than that derived from the empirical model. It indicates that the magnetospheric magnetic field near the subsolar magnetopause is more compressed than prediction when the magnetopause moves inward, which may be caused by the disequilibrium of the magnetosphere when the magnetopause moves rapidly.