Authors: Yifan Huang (LANL)

We study the anisotropy of the interstellar pick-up ions in the solar wind by simulating the pitch angle scattering using MHD-PIC method, in which the electrons and solar wind ions are treated as fluid and the PUIs are treated as particles. We calculate the mean free path of the interstellar PUIs in cases with different angles between solar wind velocity and magnetic field, and in cases with different densities of PUIs. Our results can be used to compare with the observed anisotropy level of PUIs by the Ulysses spacecraft.