The Instability of Rotating Plasmas in the Azimuthal Magnetic Field

摘要

In the publication by Velikhov [1], the instability of a magnetized rotating medium had been shown, which was called later the magnetorotational instability (MRI). In this case, two problems corresponding to the cylindrical geometry of the longitudinal and azimuthal magnetic fields were considered. In this connection, we can speak about two Velikhov problems. The first one, i.e., the MRI in the longitudinal magnetic field, has already been subjected to thorough analysis in a number of studies. The discussion was initiated by Balbus and Howley [2], who apply the MRI concept to the problem of anomalous viscosity in accretion disks [3] (see also the review [4] of these authors). However, the second Velikhov problem also is important insofar as it is impossible to ignore the azimuth magnetic-field component in accretion disks [5]. This is the problem that is analyzed in the present paper.