Stability of longitudinally homogeneous z-pinch with current above the Pease-Braginski limit

Stability of equilibrium state of radiation-cooled dense z-pinch is analized in zero-dimensional MHD approximation. For copper and aluminium instability range is calculated taking into account varied plasma composition and optical transparency in the plane of current-running mass variables. The mass lower estimate being ≅ 0.1 mug/cm above which the charge is unstable is presented. Using calculations it is shown that instability is of threshold character and results in strongly nonlinear oscillations with powerful radiation release