We present a relaxation system for ideal MHD that is an extension
of the Suliciu relaxation system for the Euler equations
of gas dynamics. From it one can derive
approximate Riemann solvers with three or seven waves, that
generalize the HLLC solver for gas dynamics.
Under some subcharacteristic
conditions, the solvers satisfy discrete
entropy inequalities, and preserve positivity of density and
internal energy. The subcharacteristic conditions are nonlinear constraints on
the relaxation parameters relating them to the initial states and the
intermediate states of the approximate Riemann solver itself.
The 7-wave version of the solver is able to resolve exactly all material
and Alfven isolated contact discontinuities.
Practical considerations and numerical results will be provided in another paper.
Return to personal page