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Advances in Astronomy
Volume 2013, Article ID 429303, 10 pages
Research Article

Diffusion Coefficients, Short-Term Cosmic Ray Modulation, and Convected Magnetic Structures

1Blackett Laboratory, Imperial College, London SW7 2BZ, UK
2Space Sciences Department, The Aerospace Corporation, Los Angeles, CA 90009, USA

Received 2 August 2012; Revised 18 January 2013; Accepted 19 January 2013

Academic Editor: José F. Valdés-Galicia

Copyright © 2013 John J. Quenby et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Three cases of large-amplitude, small spatial-scale interplanetary particle gradients observed by the anticoincidence shield (ACS) aboard the INTEGRAL spacecraft in 2006 are investigated. The high data rates provided by the INTEGRAL ACS allow an unprecedented ability to probe the fine structure of GCR propagation in the inner Heliosphere. For two of the three cases, calculating perpendicular and parallel cosmic ray diffusion coefficients based on both field and particle data results in parallel diffusion appearing to satisfy a convection gradient current balance, provided that the magnetic scattering of the particles can be described by quasi-linear theory. In the third case, perpendicular diffusion seems to dominate. The likelihood of magnetic flux rope topologies within solar ejecta affecting the local modulation is considered, and its importance in understanding the field-particle interaction for the astrophysics of nonthermal particle phenomena is discussed.