Statistical study of linear magnetic hole structures near Earth

Abstract. The Magnetospheric Multiscale mission (MMS1) data for 8 months in the winter periods of 2017–2018 and 2018–2019, when MMS had its apogee upstream solar wind Earth's bow shock, are used to study linear magnetic holes (LMHs). These LMHs characterized by a depression more than 50 % rotation background field less then 10?. A total 406 found and, based on their magnetoplasma characteristics, split into three categories: cold (increase density, little change ion temperature), hot temperature, decrease density) sign (at least one component changes sign). occurrence rate is 2.3 per day. All basically pressure balance with ambient plasma. Most plasmas that stable against mirror-mode generation, but only half mirror-mode-stable inside.