Dust

Turning on DUST

The SCALAR and DUST flags can be used in any build to add dust as an additional fluid component to a simulation (see also the DUST build type). Note that Cholla's dust model treats dust as a passive scalar, so both flags are required. The dust field in the conserved variable arrays can be accessed using grid_enum::dust_density.

Initializing dust distribution

The initial distribution of dust can be set in the same manner as the other conserved variables in the initial conditions function (see, for example, the Clouds initial conditions function). This controls the spatial distribution and initial density of dust. The dust grain size should be set using the grain_radius keyword in the input file (in units of 0.1 micron). Invocations of the DUST macro should be wrapped in the SCALAR macro.

Dust model

The current scope of the dust model is limited to dust destruction due to sputtering, which depends on the local gas density and temperature, as well as the dust grain size. The sputtering model can be found in McKinnon et al. (2017). Because we employ the passive scalar feature of Cholla, this model treats dust as a fluid that is fully dynamically coupled to gas.