The Disk Accretion Rate for Dynamo-generated Turbulence

Abstract
Dynamo-generated,turbulence,is simulated,in a modified,shearing,box,approximation,that removes,scale invariance,and,allows,finite accretion,rates,for,a given,distance,from,the,central,object. The,effective Shakura-Sunyaev viscosity parameter, aSS, is estimated in three different ways using the resulting mass accretion rate,theheatingrate,andthehorizontalcomponentsoftheMaxwellandReynoldsstresstensors.Theresultsare stillresolutiondependent:doublingtheresolutionleadsto1.4‐1.6timeslargervaluesfortheviscosityparameter. For 63 3127 364 meshpoints,wefind,that aSS 50.007. Subject headings: accretion, accretion disks—hydrodynamics—MHD—turbulence