SIMULATION OF Z-PINCH DYNAMICS IN A HIGH-CURRENT PLASMA LENS WITH A NEW ONE-DIMENSIONAL MODEL INCLUDING FINITE PLASMA CONDUCTIVITY

The dynamics of a fast Z-pinch plasma lens was simulated with a one-di mensional model for the phase of constriction. The calculation resulte d in a realistic description-compared to experiment-of pinch dynamics and current density distribution up to the time of minimum plasma radi us, which is important to evaluate the focus quality of the lens. Equa tions of the inverse skin effect and the momentum conservation equatio n of magnetohydrodynamics were used. Due to the consideration of a fin ite plasma conductivity a finite current density distribution was comp uted, reaching 16 kA/cm(2) at its maximum, which corresponds to a tota l current of about 280 kA at pinch time. The plasma is compressed from an initial radius of 100 mm to a pinch radius of about 14 mm within 3 .33 mu s. Thus, an ion density of 1.6x10(18) cm(-3) and a temperature of 30 eV is calculated. Although no shock wave is implemented in the m odel explicitly, a sharp radial density increase appears in the contra ction phase and moves toward the axis with a velocity of up to 8x10(4) m/s. (C) 1996 American Institute of Physics.