  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
(Jatenco-Pereira & Opher 1989a, b). For the nominal values studied, f=delta
v/v_{A}=0.002 and F=varpi/Omega_{i}=0.1, where delta v, v_{A} and varpi 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 Alfven 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.
