A new model describing Forbush Decreases at Mars: combining the heliospheric modulation and the atmospheric influence  

作　　者：Jingnan Guo Robert FWimmer-Schweingruber Mateja Dumbović Bernd Heber YuMing Wang 

机构地区：[1]School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,China [2]Chinese Academy of Sciences Center for Excellence in Comparative Planetology,Hefei 230026,China [3]Institute of Experimental and Applied Physics,Christian-Albrechts-University,Kiel,DE 24118,Germany [4]Hvar Observatory,Faculty of Geodesy,University of Zagreb,Croatia

出　　处：《Earth and Planetary Physics》2020年第1期62-72,共11页地球与行星物理（英文版）

基　　金：supported by the Strategic Priority Program of the Chinese Academy of Sciences (Grant No.XDB41000000 and XDA15017300);the Key Research Program of the Chinese Academy of Sciences (Grant No.XDPB11 and QYZDBSSW-DQC015);the CNSA pre-research Project on Civil Aerospace Technologies (Grant No.D020104);National Natural Science Foundation of China (Grant No.41842037);the German Aerospace Center (DLR) and DLR’s Space Administration grants 50QM0501, 50QM1201 and 50QM1701;support by the Croatian Science Foundation under the project 7549 (MSOC) and EUH2020 grant agreement No 824135 (project SOLARNET)

摘　　要：Forbush decreases are depressions in the galactic cosmic rays (GCRs) that are caused primarily by modulations of interplanetary coronal mass ejections (ICMEs) but also occasionally by stream/corotating interaction regions (SIRs/CIRs). Forbush decreases have been studied extensively using neutron monitors at Earth;recently, for the first time, they have been measured on the surface of another planet, Mars, by the Radiation Assessment Detector (RAD) on board the Mars Science Laboratory’s (MSL) rover Curiosity. The modulation of GCR particles by heliospheric transients in space is energy-dependent;afterwards, these particles interact with the Martian atmosphere, the interaction process depending on particle type and energy. In order to use ground-measured Forbush decreases to study the space weather environment near Mars, it is important to understand and quantify the energy-dependent modulation of the GCR particles by not only the pass-by heliospheric disturbances but also by the Martian atmosphere. Accordingly, this study presents a model that quantifies both at the Martian surface and in the interplanetary space near Mars the amplitudes of Forbush decreases at Mars during the pass-by of an ICME/SIR by combining the heliospheric modulation of GCRs with the atmospheric modification of such modulated GCR spectra. The modeled results are in good agreement with measurements of Forbush decreases caused by ICMEs/SIRs based on data collected by MSL on the surface of Mars and by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft in orbit. Our model and these findings support the validity of both the Forbush decrease description and Martian atmospheric transport models.Forbush decreases are depressions in the galactic cosmic rays(GCRs) that are caused primarily by modulations of interplanetary coronal mass ejections(ICMEs) but also occasionally by stream/corotating interaction regions(SIRs/CIRs). Forbush decreases have been studied extensively using neutron monitors at Earth; recently, for the first time, they have been measured on the surface of another planet, Mars, by the Radiation Assessment Detector(RAD) on board the Mars Science Laboratory’s(MSL) rover Curiosity. The modulation of GCR particles by heliospheric transients in space is energy-dependent; afterwards, these particles interact with the Martian atmosphere, the interaction process depending on particle type and energy. In order to use ground-measured Forbush decreases to study the space weather environment near Mars, it is important to understand and quantify the energy-dependent modulation of the GCR particles by not only the pass-by heliospheric disturbances but also by the Martian atmosphere. Accordingly, this study presents a model that quantifies — both at the Martian surface and in the interplanetary space near Mars — the amplitudes of Forbush decreases at Mars during the pass-by of an ICME/SIR by combining the heliospheric modulation of GCRs with the atmospheric modification of such modulated GCR spectra. The modeled results are in good agreement with measurements of Forbush decreases caused by ICMEs/SIRs based on data collected by MSL on the surface of Mars and by the Mars Atmosphere and Volatile Evolutio N(MAVEN) spacecraft in orbit. Our model and these findings support the validity of both the Forbush decrease description and Martian atmospheric transport models.

关 键 词：ICME and Forbush decreases space weather at Mars Mars:atmosphere GCR radiation 

分 类 号：P185.3[天文地球—天文学]