Fire-hose instability of the torsional Alfven oscillation as a mechanism of plasma layering in an experimental coronal solar loop-type magnetic arch

The compact experimental setup ``Solar Wind'' (IAP RAS) is designed for modeling plasma processes in a magnetic arch of the coronal solar loop type. Arc discharges at the bases of the arch create plasma with a significantly increased ionic temperature along the magnetic force line. Optical images show that the plasma rope is stratified into two belts along the upper and lower vaults of the arch or as a near-wall cylindrical layer. The system stratifies when the longitudinal ionic pressure at the top of the loop is 2 times the magnetic pressure. The indicated pressure ratio coincides with the threshold value for the development of the fire-hose instability of the Alfven wave in a plasma with temperature anisotropy. We propose a variant of the growing torsional Alfven oscillation as a mechanism for the formation of a cylindrical layer along the plasma tube wall.