Simulation of Pickup ions - Local Interstellar Medium Interactions in the Outer Heliosphere

Abstract

The energetic neutral atoms (ENAs) received by Interstellar Boundary Explorer (IBEX) shows a ribbon structure of the ENA source around the heliopause, the plasma boundary of solar system. The reason behind it is still a mystery. Hybrid simulations in two-dimensional space and three-dimensional velocity dimensions with continuous injection of pickup ions (PUIs) discussed in this dissertation provide insight into the plasma processes that are responsible for the pitch angle scattering of PUIs outside the heliopause. The isotropization time of the PUIs is estimated and discussed in relation to two variants of the secondary ENA mechanism as an explanation of the IBEX ENA ribbon, showing the time is too short for the conventional model and providing ground for further studies.