Sphere Wind Simulation

Using the hot wind model discussed in the previous post, the following simulations show the evolution of a spherical cloud of cool, constant density gas. The sphere has a radius \(R_{\mathrm{cloud}} = 5\,\mathrm{pc}\), and a density \(n_h = 1.0 \,\mathrm{cm}^{-3}\). It is initially in pressure equilibrium with the hot wind, with wind parameters chosen at a distance of \(R_{*} = 1\,\mathrm{kpc}\): \(n_{wind} = 7.683798 \times 10^{-4}\,\mathrm{cm}^{-3}\), \(v_{wind} = 1.229560\,\mathrm{km}\,\mathrm{s}^{-1}\), and \(T_{wind} = 3.991611 \times 10^{6}\,\mathrm{K}\). The Mach number of the wind at this point is \(M \approx 5.25\).

Below are snapshots from two simulations - one showing an adiabatic cloud, and one showing a cloud that is allowed to radiatively cool (the cooling sim also includes background heating from photoionization). Snapshots are shown every 200 kyr. The box has dimensions \(50 \times 50 \times 100\) pc, and the cloud has an initial resolution of 32 cells / \(R_{\mathrm{cloud}}\).

The following images show the evolution of an adiabatic simulation:

This evolution can be contrasted with the radiatively cooling case: