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McDonald et al. 2002
McDonald, F.B., Klecker, B., McGuire, R.E. and Reames, D.V. (2002). Relative recovery of galactic and anomalous cosmic rays at 1 AU: Further evidence for modulation in the heliosheath. Journal of Geophysical Research 107: doi: 10.1029/2001JA000206. issn: 0148-0227.

For solar cycle 22 the large-scale interplanetary disturbances produced by the intense solar activity of March/June 1991 had a long-term effect on the recovery of galactic cosmic rays throughout the heliosphere that persisted for almost 5 years. At 1 AU, the recovery of 13 MeV/nucleon anomalous cosmic ray oxygen (ACR O+) is much more rapid than that of 265 MeV/nucleon galactic cosmic ray helium (GCR He), consistent with previous observations in the distant heliosphere <McDonald et al., 2000> and strengthening the concept that the region of the heliosheath plays an important role in the modulation of galactic cosmic rays. A comparison of the time histories of GCR He and ACR O+ at 1 and 44 AU observations suggest the recovery moves from the distant heliosphere inward toward 1 AU for this particular phase of the heliomagnetic cycle. There is a very low relative modulation potential, Φ, between 1 and 70 AU of 116 ¿ 6 MV for GCR He at solar minimum using the force field approximation. When combined with the small radial intensity gradients in the distant heliosphere, a much lower modulation potential is implied between 1 AU and the termination shock at solar minimum than had been assumed previously. There is no effect on the 13 MeV/nucleon ACR O+ intensity as the inclination of the heliospheric neutral current sheet decreases from 32¿ to its minimum value of 8¿.

BACKGROUND DATA FILES

Abstract

Keywords
Interplanetary Physics, Cosmic rays, Interplanetary Physics, Heliopause and solar wind termination, Interplanetary Physics, Interplanetary shocks, Interplanetary Physics, Solar cycle variations, Solar Physics, Astrophysics, and Astronomy, Coronal mass ejections
Journal
Journal of Geophysical Research
http://www.agu.org/journals/jb/
Publisher
American Geophysical Union
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