Accretion disc viscosity : how big is alpha ?
نویسندگان
چکیده
We consider observational and theoretical estimates of the accretion disc viscosity parameter α. We find that in thin, fully-ionized discs, the best observational evidence suggests a typical range α ∼ 0.1 − 0.4, whereas the relevant numerical simulations tend to derive estimates for α which are an order of magnitude smaller. We discuss possible reasons for this apparent discrepancy.
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