Plasma formation with regulated electric potential distribution in SMOLA helical mirror device

This paper presents experimental results from the SMOLA device, constructed at the Budker Institute of Nuclear Physics, to verify the concept of helical mirror confinement. The experiments discussed focus on collision regimes and plasma rotation in the transport section, controlled primarily by the axisymmetric plasma gun. The plasma gun of the SMOLA comprises a lanthanum hexaboride cathode, a hollow copper anode and magnetic coils, forming a magnetron discharge with a high degree of ionisation and a radial electric field for E × B drift. Ion collisionality is adjustable from collisional to collisionless via magnetic configuration and gas feed of the plasma gun. The main processes in collisions are the ion–ion binary collisions. Electric potential radial distribution, governed by discharge voltage, the anode geometry and its potential, enables E × B plasma rotation such that the axial magnetic mirrors velocity in the rotating plasma reference frame can be comparable to the ion thermal velocity ( VZ VTᵢ ), which realises conditions for effective plasma confinement.