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SUMMARY:Turbulent convection in accretion discs - Lesur\, G (Cambridge)
DTSTART:20090817T143000Z
DTEND:20090817T145000Z
UID:TALK19510@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:Transport of angular momentum has always been a central proble
 m of accretion disc theory. Since the discovery of the magnetorotational i
 nstability in accretion discs by Balbus and Hawley (1991)\, MRI-driven tur
 bulence is believed to be the best candidate to explain anomalous transpor
 t in discs. \n\nDespite this result\, several other routes to turbulence h
 ave been considered over the last two decades\, with limited success. A po
 ssible alternative to MRI turbulence is turbulent convection\, driven by a
 n unstable vertical entropy gradient in the disc. Several studies have sho
 wn that convection was actually transporting angular momentum inward\, and
  is therefore not favourable to accretion. \n\nIn this presentation\, I wi
 ll revisit the problem of turbulent convection in accretion discs\, using 
 modern numerical methods. In particular\, I will show that this hydrodynam
 ic process could actually drive outward angular momentum transport if cert
 ain conditions are met\, with an efficiency compatible with protoplanetary
  discs observations. 
LOCATION:Seminar Room 1 Newton Institute
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