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Determination of interplanetary coronal mass ejection geometry and orientation from ground-based observations of galactic cosmic rays

Citation

Kuwabara, T and Bieber, JW and Evenson, P and Munakata, K and Yasue, S and Kato, C and Fushishita, A and Tokumaru, M and Duldig, ML and Humble, JE and Silva, MR and Dal Lago, A and Schuch, NJ, Determination of interplanetary coronal mass ejection geometry and orientation from ground-based observations of galactic cosmic rays, Journal of Geophysical Research-Space Physics, 114, (5) pp. 1-10. ISSN 0148-0227 (2009) [Refereed Article]


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Copyright Statement

Copyright 2009 American Geophysical Union.

Official URL: http://www.agu.org/pubs/

DOI: doi:10.1029/2008JA013717

Abstract

We have developed a method for determining interplanetary coronal mass ejection (ICME) geometry from galactic cosmic ray data recorded by the ground-based muon detector network. The cosmic ray density depression inside the ICME, which is associated with a Forbush decrease, is represented by an expanding cylinder that is based on a theoretical model of the cosmic ray particle diffusion. ICME geometry and orientation are deduced from observed time variations of cosmic ray density and density gradient and are compared with those deduced from a magnetic flux rope model. From March 2001 to May 2005, 11 ICME events that produced Forbush decreases >2% were observed, and clear variations of the density gradient due to ICME passage were observed in 8 of 11 events. In five of the eight events, signatures of magnetic flux rope structure (large, smooth rotation of magnetic field) were also seen, and the ICME geometry and orientation deduced from the two methods were very similar in three events. This suggests that the cosmic ray-based method can be used as a complementary method for deducing ICME geometry especially for events where a large Forbush decrease is observed.

Item Details

Item Type:Refereed Article
Research Division:Physical Sciences
Research Group:Astronomical and Space Sciences
Research Field:High Energy Astrophysics; Cosmic Rays
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Physical Sciences
Author:Humble, JE (Dr John Humble)
ID Code:58882
Year Published:2009
Web of Science® Times Cited:18
Deposited By:Physics
Deposited On:2009-11-03
Last Modified:2015-02-10
Downloads:0

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