Study on the plasma and runaway electrons on the current excitation without inductor in the B-20 torsatron

Current excitation without inductor in the B-20 torsatron with plasma parameters n=1012-1013 and Tsub(e)=40-60 eV is studied. Study of plasma processes both in the current and noncurrent modes has become possible due to excitation of plasma current only at the initial stage of the discharge. Plasma conductivity measured by current and voltage turned to be an order lower than the classical one calculated for the measured electron temperature. Investigated are the discharge modes in which a large number of runaway electrons appear (N approximately 2-ix1011) are investigated. It is shown that the runaway process exists continuously during the whole discharge. When attaining a certain boundary energy the value of which depends on the confinement properties of the trap the accelerated electrons leave the volume of confinement