Numerical studies of shocked magnetic gas clouds - I

A numerical technique is used for the analysis of non-steady flow fields generated by shocks in interstellar gas. The governing set of Eulerian, partial differential, equations describing the system are integrated using a finite difference scheme which is based on an extension of the fluid in cell (FLIC) method. This paper investigates the influence of large scale interstellar magnetic fields on the early evolution (time $$\leqslant3.0\times10^6\enspace \text {yr}$$) of a high density gas cloud (mass ∼ 700M_⊙) which is hit by a strong shock wave. The incident shock is assumed a priori to be driven by a spiral density wave. Results are presented for the flow fields which develop in gaseous systems having magnetic field strengths of 0, 1 and 3 µG