Low Earth orbit assessment of proton anisotropy using AP8 and AP9 trapped proton models

The anisotropic formalism incorporates the contributions of proton narrow pitch angle (PA) and east-west (EW) effects. Within SAA, the EW anisotropy results in different level of exposure to each side of the ISS Zvezda SM, allowing angular evaluation of the anisotropic proton spectrum. While the combined magnitude of PA and EW effects at LEO depends on a multitude of factors such as trapped proton energy, orientation and altitude of the spacecraft along the velocity vector, this paper draws quantitative conclusions on the combined anisotropic magnitude differences within ISS SM target point between AP8 and AP9 models.