N. Chakrabarti et Jj. Rasmussen, Shear flow effect on ion temperature gradient vortices in plasmas with sheared magnetic field, PHYS PLASMA, 6(8), 1999, pp. 3047-3056
The effect of velocity shear on ion temperature gradient (ITG) driven vorti
ces in a nonuniform plasma in a curved, sheared magnetic field is investiga
ted. In absence of parallel ion dynamics, vortex solutions for the ITG mode
are studied analytically. It is shown that under certain conditions the co
upled equations for potential and pressure exhibit special tripolar vortex-
like structures. For the general case, however, parallel ion dynamics is in
cluded and the equation describing the stationary ITG vortex has the struct
ure of a nonlinear Poisson-type equation. Analytical as well as numerical s
olutions of this equation are presented for various possible cases. It is s
hown that, for a critical value of the velocity shear asymmetric dipolar vo
rtices can arise which are strongly modified as a localized vortex chain at
resonance. For strong velocity shear these structures are destroyed and ul
timately lead to a dominating monopolar form. The effects of magnetic shear
indicate it may destroy these structures. (C) 1999 American Institute of P
hysics. [S1070-664X(99)00108-1].