Asymptotic saturation of mode frequency for the magnetorotational instability in resistive plasmas

3rd International Conference on Mathematical Modeling in Physical Sciences

物理学;数学

Silveira, F.E.M.^1

Centro de Ciências Naturais e Humanas, Universidade Federal Do ABC, 166 Rua Santa Adélia, Bairro Bangu, Santo André SP

CEP 09.210-170, Brazil^1

关键词: Characteristic frequencies;    Dispersion relations;    Epicyclic frequencies;    Induction equations;    Instability condition;    Magnetorotational instability;    Mode frequencies;    Resistive effects;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/574/1/012071/pdf
DOI  :  10.1088/1742-6596/574/1/012071

来源: IOP

【 摘 要 】

Resistive effects are investigated on the magnetorotational instability. The main modifications with respect to the approach to the problem in the ideal limit are the introduction of the diffusive term in the induction equation and of the decay time T of the velocity field perpendicular to the magnetic field in the dispersion relation. As a result, when resistive effects are strong, it is shown that the instability condition in the ideal limit is corrected by the coefficient κ2T2, where κ denotes the epicyclic frequency. The proposed formulation is then applied to the description of the instability for a Keplerian disk and it is found that the characteristic frequency of the unstable modes saturates asymptotically to a finite value which does not depend on the distance from the central object and is fully determined by the resistivity of the disk.