ULYSSES COSPIN LET - LATITUDINAL GRADIENTS OF ANOMALOUS COSMIC-RAY O,N AND NE/

Citation
Kj. Trattner et al., ULYSSES COSPIN LET - LATITUDINAL GRADIENTS OF ANOMALOUS COSMIC-RAY O,N AND NE/, Astronomy and astrophysics, 316(2), 1996, pp. 519-527
Citations number
45
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
00046361
Volume
316
Issue
2
Year of publication
1996
Pages
519 - 527
Database
ISI
SICI code
0004-6361(1996)316:2<519:UCL-LG>2.0.ZU;2-W
Abstract
A key goal of the Ulysses mission is the measurement of the latitudina l gradient of the Anomalous Cosmic Ray (ACR) component. Earlier studie s using data from the COSPIN/LET experiment on board Ulysses together with in-ecliptic data from the HILT instrument on SAMPEX have shown a small (similar to 2% per degree) positive latitudinal gradient for ano malous oxygen in the energy range 8 to 16 MeV/n. This result is consis tent with the effects of curvature and gradient drifts in the heliosph eric magnetic field for the current polarity configuration: positively charged particles are expected to flow down to the heliographic equat or from the polar regions. In this paper we extend our previous work a nd include two additional ACR species, nitrogen (4 to 20 MeV/n) and ne on (4 to 30 MeV/n). We also present our latest results on the ACR oxyg en latitudinal gradient over an extended energy range (4 to 20 MeV/n). The period covered for all three species include the Ulysses south po lar pass, the rapid transit from the south pole to the ecliptic and a significant portion of the climb to high northern latitudes. For all s pecies and energy ranges the latitudinal gradients are between 1% and 2%, consistent with earlier studies, and show a slight tendency to lar ger gradients for higher magnetic rigidity.