Accretion Disks, Elevated

Mitch Begelman (JILA)

November 12, 2015

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Abstract: In addition to driving the turbulence that transfers angular momentum and permits accretion disks to accrete, the magnetorotational instability also creates a strong, highly organized magnetic field parallel to the disk plane. Although this field is buoyant and continuously escapes, under certain conditions it can build up to the point where it dominates other forms of pressure in supporting the disk vertically against gravity. I will discuss the properties of such “magnetically elevated” disks and show that their existence can resolve several longstanding problems in accretion disk theory.