We study the numerical approximation of a multigroup three temperature plasma
model. A reformulation of the model is proposed in order to derive robust convex
combination-based schemes. The produced schemes are naturally well-suited to
handle stiff source terms and can be analyzed. However, because of the very
large size of the resulting linear system, a direct numerical solving cannot
be performed in practice if a large number of cells or frequency groups is
used. Consequently, a decoupling procedure is presented in order to greatly
reduce the numerical cost of the method while keeping the fundamental
discrete properties. After detailing the schemes derivation followed by the
practical numerical resolution and the decoupling procedure, a numerical
analysis is performed, and strong stability properties are proven. Several
numerical test cases are carried out to demonstrate the interest of the numerical
approach.
Keywords
multigroup three temperature model, numerical schemes,
plasma physics, radiative transfer