The dependence of the viscosity in accretion discs on theshear /
نویسندگان
چکیده
We estimate the Shakura-Sunyaev viscosity parameter alpha for diierent values of the shear/vorticity ratio, =!, using local simulations of dynamo-generated turbulence. We nd that the time average of is approximately proportional to =! (at least for =! < 10). We point out that this result may have important implications for the properties of thick accretion discs, because there ! is small and would then tend to be large. Our result may also be important for accretion discs around black holes, because =! becomes large in the inner ten Schwarzschild radia due to relativistic eeects.
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