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Paper: |
Simulating the Heliosphere with Kinetic Hydrogen and Dynamic MHD Source Terms |
Volume: |
474, Numerical Modeling of Space Plasma Flows (ASTRONUM2012) |
Page: |
195 |
Authors: |
Heerikhuisen, J.; Pogorelov, N.; Zank, G. |
Abstract: |
The interaction between the ionized plasma of the solar wind (SW)
emanating from the sun and the partially ionized plasma of the local
interstellar medium (LISM) creates the heliosphere. The heliospheric
interface is characterized by the tangential discontinuity known as the
heliopause that separates the SW and LISM plasmas, and a termination
shock on the SW side along with a possible bow shock on the LISM
side. Neutral Hydrogen of interstellar origin plays a critical role in
shaping the heliospheric interface, since it freely traverses the
heliopause. Charge-exchange between H-atoms and plasma protons couples
the ions and neutrals, but the mean free paths are large, resulting in
non-equilibrated energetic ion and neutral components. In our model,
source terms for the MHD equations are generated using a kinetic approach
for hydrogen, and the key computational challenge is to resolve these
sources with sufficient statistics. For steady-state simulations,
statistics can accumulate over arbitrarily long time intervals. In
this paper we discuss an approach for improving the statistics in
time-dependent calculations, and present results from simulations of
the heliosphere where the SW conditions at the inner boundary
of the computation vary according to an idealized solar cycle. |
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