AC3 - Accretion discs and jets |
|
Speaker |
Renzi, Fabrizio |
|
Coauthors |
Giovanni Montani |
| Talk Title |
MRI in inertial MHD |
|
Abstract |
We discuss the morphology of the Magneto-rotational Instability (MRI) for a thin plasma disk configuration with a differential rotation profile when the contribution of electron inertia in the generalized Ohm's law is not negligible. We take into account the so-called corotation theorem for the background profile and accordingly we use the magnetic flux surface function as a dynamical variable. In order to select the intrinsic Alfvénic nature of the MRI, we restrict our analysis to an incompressible plasma embedded in a purely poloidal magnetic field aligned with the rotational axis. As consequence of the contribution of electron inertia, a magnetic field is generated in addition to that where the disk is placed. This additional field is responsible for the arising of eddy currents in a narrow vertical region close to the rotational plane. Those currents tends to counteract the destabilizing effect of the MRI, particularly when the typical MRI scale at its maximum growth rate is smaller than the electron skin depth, we found that the disk is stabilized by the inertial field. This study, therefore, reinforces the importance of investigating the behavior of the MRI in extended MHD theory. |
|
Talk view |
|
|
|
|