Influence of Z-Pinch Wire Geometrical Characteristics on the Generation of the Electrothermomechanical and Plasma Instabilities

The physical processes that occur at the initial stages of electrical exploding wire are crucial for plasma dynamics in pulsed-power Z-Pinch experiments. During the interaction of a pulsed current with a single wire, the generated Electro-Thermo-Mechanical (ETM) instability in the solid phase acts as a seeding mechanism for the later developed plasma instabilities. ¹ The influence of the geometrical characteristics (thickness and length of the wire) on the generation of the ETM and plasma instability is the main focus of this work. Experimental results for the expansion dynamics of the exploded wire are obtained by a modified Fraunhofer diffraction probe method, while three-frames shadowgraphic and interferometric measurements are carried out to study the plasma dynamics and the generated instabilities. Multiphysics-multiphase simulations considering the phase changes from solid to plasma state are performed to validate the experimental measurements. For varying wire thickness and length, the combination of the experimental method and multiphysics modeling is capable to describe satisfactorily the wire expansion dynamics and the growth rate of the developed instabilities.