English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We consider the radial buoyancy of vertical magnetic field lines in radiationand gas pressure dominated accretion disks. We find that in addition to radialdrift driven by turbulent diffusion and biased by the global field geometry,there are buoyancy effects which tend to move magnetic flux outward. In gaspressure dominated disks the poloidal magnetic field will move outward at arate comparable to its inward advection. On the other hand, in a radiationpressure dominated disk the poloidal magnetic field will usually move outwardfaster than it is advected inward. This implies that the fields in disks inactive galactic nuclei are generated at small radii by an internal disk dynamo.This conclusion can be avoided if the external field imposes a supersonicAlfv\'en speed within the disk without giving rise to interchangeinstabilities. In any case we note that variations in the mass transfer ratewill lead directly to a modulation of the nonthermal emission from the disksystem.Comment: 19 pages, no figures, minor revisions; Astrophysical Journal, in  pres

The Variability of Active Galactic Nuclei and the Radial Transport of Vertical Magnetic Flux