Influence of upstream solar wind on magnetic field distribution in the Martian nightside ionosphereOAEI
Influence of upstream solar wind on magnetic field distribution in the Martian nightside ionosphere
Using over eight years of Mars Atmosphere and Volatile EvolutioN(MAVEN)data,from November 2014 to May 2023,we have investigated the Martian nightside ionospheric magnetic field distribution under the influence of upstream solar wind drivers,including the interplanetary magnetic field intensity(|BIMF|),solar wind dynamic pressure(Psw),solar extreme ultraviolet flux(EUV),and Martian seasons(Ls).Our analysis reveals pronounced correlations between magnetic field residuals and both|BIMF|and Psw.Correlations observed with EUV flux and Ls were weaker—notably,magnetic field residuals increased during periods of high EUV flux and at Mars perihelion.We find that the IMF penetrates to an altitude of 200 km under a wide range of upstream conditions,penetrating notably deeper under high|BIMF|and Psw conditions.Our analysis also indicates that EUV flux and IMF cone angle have minimal impact on IMF penetration depth.Those findings provide useful constraints on the dynamic nature of Martian atmospheric escape processes and their evolution,suggesting that historical solar wind conditions may have facilitated deeper IMF penetration and higher rates of ionospheric escape than are observed now.Moreover,by establishing criteria for magnetic'quiet'conditions,this study offers new insights into the planet's magnetic environment under varying solar wind influences,knowledge that should help refine models of the Martian crustal magnetic field.
JiaWei Gao;ZhaoJin Rong;Qi Zhang;Anna Mittelholz;Chi Zhang;Yong Wei
Key Laboratory of Earth and Planetary Physics,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China||College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,ChinaSwedish Institute of Space Physics,Kiruna SE-98128,SwedenDepartment of Earth Sciences,ETH Zurich,Zurich 8092,SwitzerlandCenter for Space Physics and Department of Astronomy,Boston University,Boston,MA 02215,USA
Martian magnetic fieldexternal magnetic fieldupstream solar wind driversIMF penetration altitudemagnetic field activity indices
《地球与行星物理（英文）》 2024 (005)
728-741 / 14
This work is supported by the National Natural Science Foundation of China(Grant No.42304186),China Postdoctoral Science Foun-dation(2023M743466),the Key Research Program of Chinese Academy of Sciences(Grant No.ZDBS-SSW-TLC00103),the Key Research Program of the Institute of Geology & Geophysics,CAS(Grant No.s IGGCAS-201904,IGGCAS-202102).This research was also supported by the International Space Science Institute(ISSI)in Bern and Beijing,through ISSI/ISSI-BJ International Team project"Understanding the Mars Space Environment through Multi-Spacecraft Measurements"(ISSI Team project #23-582;ISSI-BJ Team project #58).We would like to thank the entire MAVEN team and instrument leaders for access to data and support.We thank Yongxin Pan for helpful language assistance.
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