Influencia de efectos cinéticos en la inestabilidad magneto-rotacional en discos de acreción
Abstract
The potential role of kinetic effects in the development of instabilities in accretion disks has been recently discussed in various papers. Theoretical models of different types of accretion disks (protostellar, disks associated to binary systems, AGNs), propose mechanisms able to increase the effective viscosity of the flow in order to explain the estimated accretion rates in these objects. The magneto-rotational instability (Chandrasekhar 1960, also Balbus and Hawley 1991) provides a promising mechanism to produce a turbulent regime able to increase the effective viscosity. The relevance of the Hall effect in the linear stage of this instability has been pointed out by Wardle and Ng 1999 (also Balbus and Terquem 2001). We extend this analysis including also the effect of the electronic pressure in the generalized Ohm's law. Considering both the effects of Hall and electronic pressure, we find that a sensible increase of the unstable region in Fourier space is produced whenever the external magnetic field is anti-parallel to the vector describing the angular velocity of the disk. We studied the characteristics of this instability for sub-Keplerian, Keplerian and super-Keplerian disks.
- Publication:
-
Boletin de la Asociacion Argentina de Astronomia La Plata Argentina
- Pub Date:
- 2003
- Bibcode:
- 2003BAAA...46...54M