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| Paper: |
Reconstruction Method for M1 Equations of Radiative Transfer |
| Volume: |
474, Numerical Modeling of Space Plasma Flows (ASTRONUM2012) |
| Page: |
233 |
| Authors: |
Hanawa, T.; Kanno, Y.; Harada, T. |
| Abstract: |
We propose a new method to construct numerical flux for the M1 equations
of radiative transfer. The numerical flux is expressed as an explicit function
of the energy density, E, and energy flux, F.
It is constructed from the specific
intensity distribution used to derive the closure relation. The flux has the
upwind property in the sense that it gives a physical solution
(cE >|F| > 0)
as far as the CFL condition is satisfied. Here the symbol, c, denotes the
speed of light. At the same time, it can solve passage
of a flash successfully, i.e., the radiation energy diminishes quickly after
the passage. This means the flux causes very limited numerical diffusion.
The flux can be modified by taking account of absorption, emission, and
scattering within a numerical cell. The modified flux reproduces the diffusion
approximation when the numerical cell itself has a large optical
depth. We show application to irradiated protoplanetary disks as well
as several technical test problems. |
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