We present a model where the innermost regions of accretion discs around AGN are pervaded by a large scale magnetic field of bipolar topology. It will be shown that once this field becomes large enough, a new class of accretion flow sets in where a sizable fraction of the released accretion power feeds two self-collimated jets. Such a Jet Emitting Disc has dynamical properties quite different from both the standard and advection dominated discs. It also exhibits three different thermal equilibrium branches at a given radius: two stable (cold and hot) and one intermediate unstable. The hot solution has been for instance successfully applied to the Low/Hard states of microquasars.These results pinpoint the fact that a global understanding of accretion modes around compact objects requires to reinvestigate the issue of field advection in turbulent, magnetized disks.
|Title of host publication||Proceedings of Accretion and Ejection in AGN: a Global View|
|Editors||Laura Maraschi, Gabriele Ghisellini, Roberto Della Ceca, Fabrizio Tavecchio|
|Publication status||Published - 2010|
Ferreira, J., Petrucci, P. O., Murphy, G., Zanni, C., & Henri, G. (2010). Jet Emitting Discs: a New Accretion Flow Solution. In L. Maraschi, G. Ghisellini, R. Della Ceca, & F. Tavecchio (Eds.), Proceedings of Accretion and Ejection in AGN: a Global View (Vol. 427, pp. 49-55) http://adsabs.harvard.edu/full/2010ASPC..427...49F