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Evolution of coronal mass ejections and the corresponding Forbush decreases: modelling vs. multi-spacecraft observations

Mateja Dumbovic - Hvar Observatory, Faculty of Geodesy, University of Zagreb, Croatia; Bojan Vrsnak - Hvar Observatory, Faculty of Geodesy, University of Zagreb, Croatia; Jingnan Guo - University of Science and Technology of China, China; Bernd Heber - University of Kiel, Germany; Karin Dissauer - University of Graz, Austria; Fernando Carcaboso - University of Alcala, Spain; Manuela Temmer - University of Graz, Austria; Astrid Veronig - University of Graz, Austria; Tatiana Podladchikova - Skolkovo Institute of Science and Technology, Russia; Christian Möstl - Austrian Academy of Sciences, Space Research Institute, Austria; Tanja Amerstorfer - Austrian Academy of Sciences, Space Research Institute, Austria; Anamarija Kirin - Karlovac University of Applied Sciences, Croatia

Interplanetary CMEs and Solar Particle Events


One of the very common in situ signatures of interplanetary coronal mass ejections (ICMEs), as well as other interplanetary transients, are Forbush decreases (FDs), i.e. short-term reductions in the galactic cosmic ray (GCR) flux. A two-step FD is often regarded as a textbook example, which presumably owes its specific morphology to the fact that the measuring instrument passed through the ICME head-on, encountering first the shock front (if developed), then the sheath and finally the CME magnetic structure. The interaction of GCRs and the shock/sheath region, as well as the CME magnetic structure, occurs all the way from Sun to Earth, therefore, FDs are expected to reflect the evolutionary properties of CMEs and their sheaths. We apply modelling to different ICME regions in order to obtain a generic two-step FD profile, which qualitatively agrees with our current observation-based understanding of FDs. We test these modelling efforts against a set of multi-spacecraft observations of the same event, using the Forbush decrease model for the expanding flux rope (ForbMod). We find a reasonable agreement of the ForbMod model for the GCR depression in the CME magnetic structure with multi-spacecraft measurements, indicating that modelled FDs reflect well the CME evolution.

Approaching deadlines:

Registration opens:

16 July 2020

Abstract submission opens:

16 July 2020

European Space Weather Medals:

6 September 2020

Registration deadline:

25 September 2020

Registration deadline: [extended]

10 October 2020

Abstract submission deadline:

4 September 2020