Plasma formation in metallic wire Z pinches

Area of Science:

• Plasma Physics
• Magnetohydrodynamics
• Computational Physics

Background:

• Metallic wire Z pinches are crucial for generating high-energy-density plasmas.
• Understanding plasma formation and stability is key to applications like inertial confinement fusion.

Purpose of the Study:

• To model plasma formation in metallic wire Z pinches using a 2D resistive magnetohydrodynamics code.
• To investigate the effect of wire number on plasma structure and stability in wire arrays.
• To correlate plasma structure with experimental observations of X-ray power.

Main Methods:

• Utilized a two-dimensional resistive magnetohydrodynamics code.
• Employed modified Thomas-Fermi equations of state and dense plasma transport coefficients.
• Benchmarked code against single-wire experiments, generating artificial laser schlieren and X-ray back-lighting images.

Main Results:

• Identified a persistent two-component plasma structure: a cold, dense core within a hot, low-density corona.
• Simulations showed that increasing wire numbers in arrays leads to merged wires and reduced m=0 perturbation amplitudes.
• A sharp transition to high X-ray power in aluminum wire arrays at ~40 wires correlated with a significant decrease in m=0 perturbation amplitude.

Conclusions:

• The 2D MHD model captures key aspects of plasma formation and structure in Z pinches.
• The number of wires in an array significantly influences plasma stability and X-ray output.
• Reduced perturbations, particularly m=0, are critical for achieving high X-ray power in wire array Z pinches, mitigating the Rayleigh-Taylor instability.