Charge sign dependence of cosmic ray modulation near a rigidity of 1 GV

Citation
Jm. Clem et al., Charge sign dependence of cosmic ray modulation near a rigidity of 1 GV, J GEO R-S P, 105(A10), 2000, pp. 23099-23105
Citations number
42
Categorie Soggetti
Space Sciences
Journal title
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
ISSN journal
21699380 → ACNP
Volume
105
Issue
A10
Year of publication
2000
Pages
23099 - 23105
Database
ISI
SICI code
0148-0227(20001001)105:A10<23099:CSDOCR>2.0.ZU;2-0
Abstract
New observations of electron fluxes made in 1997 and 1998 extend our ongoin g investigation of the relative modulation of positively and negatively cha rged particles. We compare electron fluxes measured on high-altitude balloo n flights with continuing observations of helium fluxes from the IMP 8 spac ecraft and present new measurements of the primary cosmic ray positron abun dance in 1997 and 1998. Electron fluxes during the 1984-1990 period show a flat topped distribution, whereas the positively charged He fluxes show a p eaked distribution, with the peak in 1987. This is expected from modulation theory, including the role of drifts when the northern heliospheric magnet ic field is inward, and the southern heliospheric field is outward. From 19 90 to 1999, data are consistent with an inverse relationship, but electron data are too sparse to allow a definitive statement. Near a rigidity of 1 G V the relative abundance of electrons and helium nuclei is a weal; function of the tilt angle of the heliospheric current sheet.