EGU22-11343
https://doi.org/10.5194/egusphere-egu22-11343
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Characteristics of a long-lived CIR and analytical modelling of the corresponding depression in the GCR flux

Mateja Dumbovic1, Bojan Vrsnak1, Bernd Heber2, Manuela Temmer3, Patrick Kuhl2, and Anamarija Kirin
Mateja Dumbovic et al.
  • 1University of Zagreb, Faculty of Geodesy, Hvar Observatory, Zagreb, Croatia (mdumbovic@geof.hr)
  • 2Christian-Albrechts University in Kiel, Department of Extraterrestrial Physics
  • 3University of Graz, Institute of Physics

We observe a long-lived CIR recurring in 27 consecutive Carrington rotations 2057-2083 in the time period from June 2007 - May 2009. We characterize the in situ measurements of this long-lived CIR as well as the corresponding depression in the GCR count observed by SOHO/EPHIN, and analyze them throughout different rotations. We find that the inverted GCR count time-profile correlates well with that of the flow speed throughout different rotations. We perform a statistical analysis and find the GCR count amplitude correlated to the peak in the magnetic field and flow speed, as expected based on previous statistical studies. In order to characterize a generic CIR profile for modelling purposes, we perform the superposed epoch analysis using relative values of the key parameters. Based on the observed properties we propose a simple analytical model starting from the basic Fokker-Planck equation. We employ a convection-diffusion GCR propagation model and apply it to the solar wind and interplanetary magnetic field properties observed for the analyzed long-lived CIR. Our analysis demonstrates a very good match of the model results and observations.

How to cite: Dumbovic, M., Vrsnak, B., Heber, B., Temmer, M., Kuhl, P., and Kirin, A.: Characteristics of a long-lived CIR and analytical modelling of the corresponding depression in the GCR flux, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11343, https://doi.org/10.5194/egusphere-egu22-11343, 2022.

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