Role of q Profile for Plasma Confinement in the Multimirror Trap GOL-3

Dense plasma heating by a relativistic electron beam and its confinement are studied in the multiple mirror trap GOL-3. Axial currents, which exist in the system, cause helical structure of the magnetic field. The safety factor q is shown to be below unity on the axis. Experimental data on the distribution and evolution of currents, structure of the magnetic field, and their influence on confinement and on MHD activity are discussed.