%0 Conference Proceedings %@holdercode {isadg {BR SPINPE} ibi 8JMKD3MGPCW/3DT298S} %@nexthigherunit 8JMKD3MGPCW/3ETL868 8JMKD3MGPCW/3EU29DP 8JMKD3MGPCW/3EUFCFP %@resumeid %@resumeid %@resumeid %@resumeid %@resumeid %@resumeid %@resumeid %@resumeid %@resumeid %@resumeid %@resumeid 8JMKD3MGP5W/3C9JHTS %@resumeid %@resumeid 8JMKD3MGP5W/3C9JGH3 %@resumeid 8JMKD3MGP5W/3C9JHUD %@usergroup administrator %@usergroup seeger05 %@usergroup administrator %3 ICRC2007_Kuwabara Determination of ICME Geometry and Orientation from Ground .. pdf.pdf %B 30 Th International Cosmic Ray Conference %X We have developed a method for determining ICME (Interplanetary coronal mass ejection) geometry from galactic cosmic ray data recorded by the ground-based muon detector network. The cosmic ray density depression inside the ICME, which is the cause of a Forbush decrease, is represented as an expanding cylinder based on a theoretical model of the cosmic ray particle diffusion. ICME geometry and orientation are deduced from observed time variations of density and density gradient, and are compared with that 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 3 of these 8 events, clear 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. This suggests that the cosmic ray-based method may provide a more robust method for deducing ICME geometry than the flux rope method for events where a large Forbush decrease is observed. %T Determination of ICME Geometry and Orientation from Ground Based Observations of Galactic Cosmic Rays %@tertiarytype Poster Session %@secondarytype PRE CI %8 July 3 - 11 %@visibility shown %@group %@group %@group %@group %@group %@group %@group %@group %@group %@group RSU-INPE-MCT-BR %@group RSU-INPE-MCT-BR %@group DAE-INPE-MCT-BR %@group DGE-INPE-MCT-BR %@group RSU-INPE-MCT-BR %@secondarykey INPE--PRE/ %2 sid.inpe.br/mtc-m17@80/2007/11.20.22.26.07 %@affiliation Bartol Research Institute and Department of Physics and Astronomy, University of Delaware %@affiliation Bartol Research Institute and Department of Physics and Astronomy, University of Delaware %@affiliation Bartol Research Institute and Department of Physics and Astronomy, University of Delaware %@affiliation Department of Physics, Shinshu University %@affiliation School of General Education, Shinshu University %@affiliation Department of Physics, Shinshu University %@affiliation STE Laboratory, Nagoya University %@affiliation Australian Antarctic Division %@affiliation School of Mathematics and Physics, University of Tasmania %@affiliation National Institute for Space Research %@affiliation National Institute for Space Research %@affiliation National Institute for Space Research %@affiliation National Institute for Space Research %@affiliation Southern Regional Space Research Center - CRS/INPE %4 sid.inpe.br/mtc-m17@80/2007/11.20.22.26 %D 2007 %A Kuwabara, Takao, %A Bieber, John, %A Evenson, Paul, %A Munakata, Kazuoki, %A Yasue, Shin-ichi, %A Kato, Chihiro, %A Fujii, Zenjiro, %A Duldig, Marcus, %A Humble, John, %A Silva, Marlos rockenbach da, %A Trivedi, Nalin Babulal, %A Gonzalez, Walter, %A Lago, Alisson Dal, %A Schuch, Nelson Jorge, %C Yucatan, Mexico %@area CEA