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Detailed Reference Information |
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. |
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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¿. |
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BACKGROUND DATA FILES |
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Abstract |
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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 |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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