| Name | Type | Default | Description |
|---|---|---|---|
| courantpar | double precision | None | The Courant (CFL) number used for the simulation |
| dtpar | double precision | None | If dtpar is positive, it sets the timestep dt, otherwise courantpar is used to limit the time step based on the Courant condition. |
| dtdiffpar | double precision | None | For resistive MHD, the time step is also limited by the diffusion time: \f$ dt < dtdiffpar \times dx^2/eta \f$ |
| typecourant | character(len=std_len) | None | How to compute the CFL-limited time step. Options are 'maxsum': max(sum(c/dx)); 'summax': sum(max(c/dx)) and 'minimum: max(c/dx), where the summations loop over the grid dimensions and c is the velocity. The default 'maxsum' is the conventiontal way of computing CFL-limited time steps. |
| slowsteps | integer | None | If > 1, then in the first slowsteps-1 time steps dt is reduced by a factor \f$ 1 - (1- step/slowsteps)^2 \f$ |