Forbush decreases (FDs) are depletions in the galactic cosmic ray (GCR) count rate that last typically for about a week and can be caused by coronal mass ejections (CMEs) or corotating interacting regions (CIRs). Fast CMEs that drive shocks cause large FDs that often show a two-step decrease where the first step is attributed to the shock/sheath region, while the second step is attributed to the closed magnetic structure. Since the difference in size of shock and sheath region is significant, and since there are observed effects that can be related to shocks and not necessarily to the sheath region we expect that the physical mechanisms governing the interaction with GCRs in these two regions are different. We therefore aim to analyze interaction of GCRs with heliospheric shocks only. We approximate the shock by a structure where the magnetic field linearly changes with position within this structure. We assume protons of different energy, different pitch angle and different incoming direction. We also vary the shock parameters such as the magnetic field strength and orientation, as well as the shock thickness. The results demonstrate that protons with higher energies are less likely to be reflected. Also, thicker shocks and shocks with stronger field reflect protons more efficiently.
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Belov, A.V.: 2009, Forbush effects and their connection with solar, interplanetary and geomagnetic phenomena. In: Gopalswamy, N., Webb, D.F. (eds.) Universal Heliophysical Processes, IAU Symposium257, 439. DOI . ADS .
Belov, A.V., Dorman, L.I., Eroshenko, E.A., Iucci, N., Villoresi, G., Yanke, V.G.: 1995, Search for predictors of Forbush decreases. In: International Cosmic Ray Conference, 4, 888. ADS .
Cane, H.V., Richardson, I.G., Wibberenz, G.: 1995, The response of energetic particles to the presence of ejecta material. In: International Cosmic Ray Conference4, 377. ADS .
Le Roux, J.A., Potgieter, M.S.: 1991, The simulation of Forbush decreases with time-dependent cosmic-ray modulation models of varying complexity. Astron. Astrophys.243, 531. ADS .
Lingri, D., Mavromichalaki, H., Belov, A., Abunina, M., Eroshenko, E., Abunin, A.: 2019, An extended study of the precursory signs of Forbush decreases: new findings over the years 2008 – 2016. Solar Phys.294(6), 70. DOI . ADS .
Lockwood, J.A.: 1971, Forbush decreases in the cosmic radiation. Space Sci. Rev.12, 658. DOI .
Lockwood, J.A., Webber, W.R., Jokipii, J.R.: 1986, Characteristic recovery times of Forbush-type decreases in the cosmic radiation. I – Observations at Earth at different energies. J. Geophys. Res.91, 2851. DOI . ADS .
Melkumyan, A.A., Belov, A.V., Abunina, M.A., Abunin, A.A., Eroshenko, E.A., Yanke, V.G., Oleneva, V.A.: 2019, Comparison between statistical properties of Forbush decreases caused by solar wind disturbances from coronal mass ejections and coronal holes. Adv. Space Res.63(2), 1100. DOI . ADS .
Munakata, K., Yasue, S., Kato, C., Kota, J., Tokumaru, M., Kojima, M., Darwish, A.A., Kuwabara, T., Bieber, J.W.: 2006, On the cross-field diffusion of galactic cosmic rays into an ICME. Solar Terrestrial (ST), Advances in Geosciences2, 115. DOI . ADS .
Quenby, J.J., Mulligan, T., Blake, J.B., Mazur, J.E., Shaul, D.: 2008, Local and nonlocal geometry of interplanetary coronal mass ejections: Galactic cosmic ray (GCR) short-period variations and magnetic field modeling. J. Geophys. Res.113, A10102. DOI . ADS .
Subramanian, P., Antia, H.M., Dugad, S.R., Goswami, U.D., Gupta, S.K., Hayashi, Y., Ito, N., Kawakami, S., Kojima, H., Mohanty, P.K., Nayak, P.K., Nonaka, T., Oshima, A., Sivaprasad, K., Tanaka, H., Tonwar, S.C. (The Grapes-3 Collaboration): 2009, Forbush decreases and turbulence levels at coronal mass ejection fronts. Astron. Astrophys.494, 1107. DOI . ADS .
Wibberenz, G., Le Roux, J.A., Potgieter, M.S., Bieber, J.W.: 1998, Transient effects and disturbed conditions. Space Sci. Rev.83, 309. ADS .
BV and MD acknowledge a support by the Croatian Science Foundation under the project 7549 “Millimeter and submillimeter observations of the solar chromosphere with ALMA”. The research leading to these results has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 745782 (ForbMod).
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Kirin, A., Vršnak, B., Dumbović, M. et al. On the Interaction of Galactic Cosmic Rays with Heliospheric Shocks During Forbush Decreases. Sol Phys 295, 28 (2020). https://doi.org/10.1007/s11207-020-1593-5
- Cosmic rays, galactic
- Magnetic fields, models
- Waves, magnetohydrodynamic, shock
- Coronal mass ejections