engleski

TRACKING AND VALIDATING ICMES PROPAGATING TOWARDS MARS USING STEREO HELIOSPHERIC IMAGERS COMBINED WITH FORBUSH DECREASES DETECTED BY MSL/RAD

The Radiation Assessment Detector (RAD) instrument onboard the Mars Science Labora- tory (MSL) mission’s Curiosity rover has been measuring galactic cosmic rays (GCR) as well as solar energetic particles (SEP) on the surface of Mars for more than 6 years since its landing in August 2012. The observations include a large number of Forbush decreases (FD) caused by interplanetary coronal mass ejections (ICMEs) and/or their associated shocks shielding away part of the GCR particles with their turbulent and enhanced magnetic fields while passing Mars. This study combines MSL/RAD FD measurements and remote tracking of ICMEs using the STEREO Heliospheric Imager (HI) telescopes in a statistical study for the first time. The large dataset collected by HI makes it possible to analyze 149 ICMEs propagating towards MSL both during its 8-month cruise phase and after its landing on Mars. We link 45 of the events observed at STEREO-HI to their corresponding FDs at MSL/RAD and study the accuracy of the ICME arrival time at Mars predicted from HI data using different methods. We also investigate the properties of the FD themselves and how they compare to measurements at Earth.

coronal mass ejections, forbush decreases, multi-spacecraft observations

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