Alfvenic heating of protostellar accretion disks

We investigate the effects of heating generated by damping of Alfven waves on protostellar accretion disks. Two mechanisms of damping are investigated, nonlinear and turbulent, which were previously studied in stellar winds. For the nominal values studied, f = delta v/v(A) = 0.002 and F = (w) over bar/Omega(l) = 0.1, where delta v, v(A), and (w) over bar are the amplitude, velocity, and average frequency of the Alfven wave, respectively, and Omega(i) is the ion cyclotron frequency, we find that viscous heating is more important than Alfvenic heating for small radii. When the radius is greater than 0.5 AU, Alfvenic heating is more important than viscous heating. Thus, even for the relatively small value of f = 0.002, Alfvenic heating can be an important source of energy for ionizing protostellar disks, enabling angular momentum transport to occur by the Balbus-Hawley instability.