Electron vortexes in high-current plasma lens

High-current plasma lens (PL) collective processes due to unremovable radial gradients of the magnetic field in the ion beam focusing direction were reported by the authors in 1992. There, the theoretical analysis of the linear growth stage of a small-scale instability was presented. Now the authors consider PL hydrodynamic instability using nonlinear approximation. It is shown, using the example of high-current PL, that the drift motion of electrons in variable electric fields caused by the principally unremovable radial gradient of the magnetic field axial component is transformed into the set of single vortex structures. The nonlinear differential equation of the electric potential describing such structures is received and its solutions are found for different configurations of external magnetic fields. It is shown that such kinds of vortices can be stable. Computer models for such kind of vortices have been created. Creation of vortices limits the maximum values of space electrostatic fields in plasmaoptics. In the low current regime of the PL with strong ion beam space charge overcompensation, the equation obtained describes the nonlinear motion of the electron fluid caused by diocotron instability