The influence of an induced axial magnetic field on plasma dynamics and radiative characteristics of $Z$ pinches is investigated. An axial magnetic field was induced in a novel $Z$-pinch load: a double planar wire array with skewed wires (DPWAsk), which represents a planar wire array in an open magnetic configuration. The induced axial magnetic field suppressed magneto-Rayleigh-Taylor (MRT) instabilities (with $m$ $=$ 0 and $m$ $=$ 1 instability modes) in the $Z$-pinch plasma. The influence of the initial axial magnetic field on the structure of the plasma column at stagnation was manifested through the formation of a more uniform plasma column compared to a standard double planar wire array (DPWA) load [V. L. Kantsyrev et al., Phys. Plasmas 15, 030704 (2008)]. The DPWAsk load is characterized by suppression of MRT instabilities and by the formation of the sub-keV radiation pulse that occurs before the main x-ray peak. Gradients in plasma parameters along the cathode-anode gap were observed and analyzed for DPWAsk loads made from low atomic number $Z$ (Al) and mid-$Z$ (brass) wires.

• Received 18 April 2011

DOI:https://doi.org/10.1103/PhysRevE.84.046408