Magnetically Heated Accretion Disk Coronae

Expect strong B:

Keplerian Shear+convectionBouyancy Loops

Observe:

Power law flickeringEmission Lines (Horne & Saar)Jets

Ueno et al.

Early Scenario

Galeev, Rosner & Vaiana

Black Hold Disk: Cygnus X-1

Scaling like solar coronal loops

Thermal Conduction + Radiation or Compton Cooling

B in equipartion within disk

T ~ 5x108 , ne ~ 10 19

Magnetorotational Instability

Balbus & Hawley

Viscosity >> MolecularConvection doesn’t work

Miller & Stone

Poynting flux ~ 25% Ediss

Sheets?

Low β Corona

Nanoflares? Pavlidou et al.

Cellular automaton model

Naturally gives power law

Angular momentum transfer byReconnection in corona alone

CMEs?? Strong winds sometimes

Can collimate flow (Williams)