The energy spectra (40 to 300 MeV/n) of galactic cosmic ray particles (C, N, O, Ne, Mg, Si, and Fe) observed by the HEP-HI silicon detector telescope onboard the GEOTAIL satellite were investigated over the period from January 1993 to May 1996, from the viewpoint of solar modulation. From the GEOTAIL data and those of relativistic heavy particles observed by HEAO-3, the modulation potential φ was obtained by using a solution of the Fokker-Plank equation with the "force-field" approximation. In the equation the diffusion coefficient was used as adjustable parameter, under the assumptions of a fixed velocity of solar wind (400km/sec) and the radius of the heliosphere of 50AU. The time variation of the modulation potential thus obtained is compared with that obtained from the CLIMAX neutron monitor. A reasonable correlation between both time variations is found when five months delay is applied to the results obtained by the HEP-HI telescope.
|Number of pages||4|
|Journal||Advances in Space Research|
|Publication status||Published - 1999|
ASJC Scopus subject areas
- Space and Planetary Science
- Astronomy and Astrophysics