Charge sign dependent modulation: Ulysses COSPIN/KET results
Sierks, H.; Kunow, H.; Bothmer, V.; Heber, Bernd; Wibberenz, G.; Potgieter, M. S.; Posner, A.; Ferrando, P.; Raviart, A.; Paizis, C.; Muller-Melin, R.
Germany, France, Italy, Switzerland
Abstract
According to drift dominated modulation models galactic cosmic ray protons and electrons respond differently to the latitudinal extension of the heliospheric current sheet. In an A 0 solar magnetic cycle intensities of ¥ positively charged particles should vary only weakly with the latitudinal extension, whereas electrons should show a much stronger response. In this paper we investigate the charge sign dependent modulation in the 1990s using measurements of 2.5 GV protons and electrons of the Cosmic and Solar Particle Investigation Kiel Electron Telescope (COSPIN/KET) on board Ulysses from the beginning of 1992 to the end of 1998. Only close to solar minimum, when the maximum latitudinal extend is below 30 , differences in the temporal variation of electrons and protons are observed.