Magnetised shearing box simulations with temperature-dependent resistivity.

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• Pierre Lesaffre (ENS, Paris)
• Friday 16 May 2008, 15:00-16:00
• MR14, DAMTP, Pav. F.

If you have a question about this talk, please contact Dr Lara Silvers.

Magnetised Keplerian disks are subject to the magnetorotational instability (MRI) which is believed to drive their state of turbulence. Isothermal shearing box simulations with a mean magnetic field have shown that the resistivity controls the saturation state of the MRI : low resistivity yields sustained turbulence (active state, hot and magnetised) whereas strong resistivity shuts it off (dead state, cold and unmagnetised). Since the resistivity is generally a (decreasing) function of temperature, the heating due to the dissipation of turbulence provides an interesting backreaction on the system. field) where heating, cooling and the temperature-dependence of the resistivity have been included. These simulations all display strong recurrent or persistent channel flows. I will show how crucial the aspect ratio of the computational box appears to be. I will finally hint at how the parasitic instabilities of the channel flow might be at the heart of the saturation process of mean field simulations.

I will show how a very schematic model can account for the transition between such two states, which can be viewed as a system with two stable phases. I will then report on shearing box simulations (with a mean

This talk is part of the DAMTP Astrophysics Seminars series.

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