1111.3075 (P. Desiati et al.)

Anisotropy of TeV Cosmic Rays and the Outer Heliospheric Boundaries    [PDF]

P. Desiati, A. Lazarian

Galactic cosmic rays are found to have a faint and broad non-dipolar anisotropy across the entire sky. In the TeV energy range, such a global anisotropy appears to have small scale features in the form of localized fractional excess regions of cosmic rays, some of which are statistically significant. The combination of different observations covering almost the whole sky show some evidence of an arc of fractional excess of TeV cosmic rays, about 20$^{\circ}$ wide, spanning from the northern to the southern equatorial hemisphere. Such an arc is located along the rim between the relative excess and deficit of the global anisotropy, and it is coincidentally not far from the sightlines perpendicular to the Local Interstellar Magnetic Field (LIMF). It is suggested that the large scale anisotropy of $<$100 TeV cosmic rays is mostly shaped by particle interactions with the turbulent ripples generated by the interaction of heliospheric and interstellar magnetic field. Such scattering processes are oriented by the LIMF and a localized fractional excess along the direction of largest pitch angle may be generated.

View original: http://arxiv.org/abs/1111.3075