Conjugate influence of current relaxation and of current-vortex sheet formation on the magnetorotational instability

15th Latin American Workshop on Plasma Physics; 21st IAEA TM on Research Using Small Fusion Devices

Silveira, F.E.M.^1 ; Galvão, R.M.O.^2

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

CEP 09210-170, Brazil^1

Instituto de Física, Universidade de São Paulo, Cidade Universitária, 187, Rua do Matão, Travessa R, São Paulo, SP

CEP 05508-090, Brazil^2

关键词: Accretion disks;    Anomalous viscosity;    Current-vortex sheet;    Keplerian disks;    Magnetorotational instability;    Marginal stability;    Resistive effects;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/591/1/012033/pdf
DOI  :  10.1088/1742-6596/591/1/012033

来源: IOP

【 摘 要 】

The conjugate influence of current relaxation and of current-vortex sheet formation on the magnetorotational instability is reviewed as firstly derived in [13]. It is shown that the relative amplification of the magnetic viscosity from marginal stability to the instability determined by the maximum growth rate is around 924% when resistive effects dominate, while the corresponding quantity is around 220% in the ideal limit. This means that the conjugate influence is much more efficient to amplify the magnetic viscosity than just the effect due to the standard magnetic tension. The results presented here may contribute to the understanding of the various processes that play a significant role in the mechanism of anomalous viscosity observed in Keplerian disks. It is argued that the new effect shall be most relevant in thin accretion disks.