Pinch discharges in a plasma near separatrix surfaces of magnetic field

The formation of pinch current layers in the vicinity of separatrix surfaces of magnetic field on the basis of analytical and numerical solution of magnetic hydrodynamics equations and experimental investigation of high-current discharges in heterogeneous external magnetic fields is studied. Dimentionless parameters are found: characterizing the relative role of damping and non-liniarity during the formation of current layers near separatrix surfaces. Analysis of self-simulative solutions of magnetic hydrodynamics equations describing a considerably non-linear stage of plasma flow near zero points has shown that formation of current layers in the vicinity of separatrixes is typical in a space heterogeneous case. The experimental investigation of gas breakdown and development of high-current discharge for similar initial and interface conditions has demonstrated that at the final stage of the discharge the plasma pinching near separatrix surfaces takes place