Solar cosmic ray distribution function under prolonged particle injection
Heading:
| 1Fedorov, YI 1Main Astronomical Observatory of the National Academy of Sciences of Ukraine, Kyiv, Ukraine |
| Kinemat. fiz. nebesnyh tel (Online) 2019, 35(5):3-24 |
| https://doi.org/10.15407/kfnt2019.05.003 |
| Start Page: Space Physics |
| Language: Russian |
Abstract: The solar cosmic ray propagation on the basis of Fokker-Planck kinetic equation is considered. It is known that solar cosmic ray distribution function averaged over a period of solar proton event contains valuable information about energetic charged particles scattering by interplanetary magnetic fields. Steady state solution of kinetic equation in small angle approximation is obtained and the dependence of angular distribution function on the distance to the particle source is analyzed. This solution is only correct when the distance to the particle source is small relative to cosmic ray mean free path, and when the particles are moving preferentially in the radial direction. The particle angular distribution on large distances to the particle source (bigger than cosmic ray mean free path) is also investigated. The analytical expression of the cosmic ray distribution function in a form of a sum of isotropic and small anisotropic components is derived. It is shown that the angular cosmic ray distribution depends essentially on the anisotropy of the cosmic ray scattering. The estimates of features of energetic charged particle scattering by interplanetary magnetic field fluctuations are made based on the observational data of some solar cosmic ray flares. |
| Keywords: cosmic rays, interplanetary magnetic field, kinetic equation |
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