The Ulysses south polar pass: Anomalous component of cosmic rays
Abstract
We have expanded our previous study of latitudinal gradients of anomalous cosmic ray oxygen (8 to 12 MeV/n and 12 to 16 MeV/n) by using also helium (11 to 20 MeV/n) as an additional component and a larger ULYSSES/LET data set including the segment up to the maximum southern latitude and the pole-to-equator segment of the mission down to 38°S. The ULYSSES observations are compared with observations in the vicinity of the Earth, provided by SAMPEX and IMP 8. The data sets cover a time period from August 1992 to end of January 1995. Only quiet time periods which contain no increases due to solar energetic particles are taken into account. Both oxygen energy channels show a decrease of the SAMPEX to ULYSSES flux ratio which is equivalent to a positive latitudinal gradient of ∼2%/degree. However, no significant latitudinal gradient for helium was found using the IMP 8 to ULYSSES flux ratio.
- Publication:
-
Geophysical Research Letters
- Pub Date:
- December 1995
- DOI:
- 10.1029/95GL02423
- Bibcode:
- 1995GeoRL..22.3349T
- Keywords:
-
- Interplanetary Physics: Cosmic rays;
- Interplanetary Physics: Interstellar gas;
- Interplanetary Physics: General or miscellaneous