MHD Turbulence in Protoplanetary Disks

Shu-ichiro Inutsuka and Takayoshi Sano

    We examine the ionization degree and and resistivity in 
protoplanetary disks, and determine the region(s) of MHD 
turbulence due to MRI.  Especially, we consider the effect of 
energy dissipatin due to MHD turbulence and its effects on 
the ionization state.  The result shows that the turbulent 
region is much wider than previously considered.  The 
implications for the planet formation in the disks are 
briefly discussed.