Entropy fixes in MHD Roe scheme

The features of the construction of entropy fixes in Roe scheme for the equations of magnetohydrodynamics are considered. It is shown that the Einfeldt fix can be used for fast magnetosonic characteristics. In the case of slow magnetosonic characteristics, it is necessary to use a modified entropy fix to align the MHD scheme with a pure gas-dynamic one. Results of test numerical calculations of the Riemann problem, demonstrating the efficiency of the proposed fixes, are presented.