Xiao-bo Qu, Yi Zhang, Liang Xue, Cheng Liu, Hong-bo Hu
The anisotropy of cosmic rays (CRs) in the solar vicinity is generally
attributed to the CR streaming due to the discrete distribution of CR sources
or local magnetic field modulation. Recently, the two dimensional large scale
CR anisotropy has been measured by many experiments in TeV-PeV energy range in
both hemispheres. The tail-in excess along the tangential direction of the
local spiral arm and the loss cone deficit pointing to the north Galactic pole
direction agree with what have been obtained in tens to hundreds of GeV. The
persistence of the two large scale anisotropy structures in such a wide range
of energy suggests that the anisotropy might be due to a global streaming of
the Galactic CRs (GCRs). This work tries to extend the observed CR anisotropy
picture from solar system to the whole galaxy. In such a case, we can find a
new interesting signature, a loop of GCR streaming, of the GCR propagation. We
further calculate the overall GCR streaming induced magnetic field, and find a
qualitative consistence with the observed structure of the halo magnetic field.
View original:
http://arxiv.org/abs/1101.5273
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