An investigation of fragmentation in collapsing magnetic gas clouds

It has been believed that the galactic magnetic field may induce fragmentation in collapsing clouds. To isolate the effects due to the magnetic field, a collapsing gas cloud (alpha = 0.24; gamma = 0.30) is simulated here using the method of Phillips (1982). Approximately 2000 particles are used in the simulation, which corresponds to a resolution of 12 x 12 x 12. No evidence of fragmentation has been found during the first 1.5 free fall times of collapse. This is possibly the result of an initially uniform field chosen for simplicity rather than a constraint of observations or any theoretical justification. Significant magnetic forces develop only after approximately one free fall time, when pressure and gravitational forces have significantly shaped and development of the cloud.