Implication of the sidereal anisotropy of ∼5 TeV cosmic ray intensity observed with the Tibet III air shower array

We show that the large-scale anisotropy of ∼5 TeV galactic cosmic ray (GCR) intensity observed by Tibet Air Shower experiment can be reproduced by the superposition of a bi-directional and uni-directional flows (UDF and BDF) of GCRs. The heliosphere is located inside the local interstellar cloud (LIC) very close to the inner edge of the LIC. If the GCR population is lower inside the LIC than outside, the BDF flow is expected from the parallel diffusion of GCRs into LIC along the local interstellar magnetic field (LISMF) connecting the heliosphere with the region outside the LIC, where the GCR population is higher. A type of the UDF, on the other hand, is expected from the B×n drift flux driven by a gradient of GCR density (n) in the LISMF (B). The LISMF orientation deduced from the best-fit direction of the BDF is almost parallel to the galactic plane and more consistent with the suggestion of Frisch (1996) than that of Lallement et al. (2005). We note that the model, if holds, yields the LISMF polarity together with its orientation. © 2007 American Institute of Physics.