Energy dissipation in clumpy magnetic clouds

The dissipation rate of kinetic energy in clumpy, magnetic, molecular clouds is calculated. The analysis includes viscous dissipation by collisions between ions and neutral molecules for slow and rapid accelerations of clump and interclump gas, hydromagnetic shock dissipation in direct collisions between clumps, and shock dissipation in waves that steepen in the interclump medium. The transfer of clump kinetic energy to the external medium along Alfvén waves is also discussed. Clumps are modeled by self-gravitating pieces inside self-gravitating clouds, with relative velocities that are either comparable to the virial-theorem velocity in the cloud or given by a velocity-separation relation for turbulence. Implications of the results for star formation in dense clouds are discussed.