Large-scale instability driven by the drift-velocity shear in crossed fields

Experimental data are presented on the properties and characteristic featur es of a newly discovered instability associated with a fairly strong sheare d rotation of a hot plasma column. The instability drives the plasma into m otion over the entire cross section of the column in the form of two vortex formations, in which the plasma rotates in opposite directions. During thi s process, the plasma escapes from the column across the magnetic field. Al ong with the rotation velocity shear, the instability is also strongly affe cted by such factors as the depth of the magnetic well and, presumably, the effect of a finite Larmor radius. A theoretical interpretation of this phe nomenon is still unavailable.