Feasibility and Performance of the Staged Z-Pinch: A One-dimensional Study with FLASH and MACH2

TL;DR

This study evaluates the feasibility of staged Z-pinch fusion using one-dimensional simulations with FLASH and MACH2 codes, comparing configurations and analyzing physics effects to inform future experimental designs.

Contribution

It provides the first detailed code-to-code comparison of staged Z-pinch simulations, highlighting the impact of physics models on performance predictions.

Findings

FLASH predicts high fuel convergence ratios (>300) for SZP1* but with lower temperatures than MACH2.

MACH2 results show higher temperatures and smaller convergence ratios.

Code comparisons reveal the influence of magnetic insulation, heat conduction, and radiation transport on Z-pinch performance.

Abstract

Z-pinch platforms constitute a promising pathway to fusion energy research. Here, we present a one-dimensional numerical study of the staged Z-pinch (SZP) concept using the FLASH and MACH2 codes. We discuss the verification of the codes using two analytical benchmarks that include Z-pinch-relevant physics, building confidence on the codes' ability to model such experiments. Then, FLASH is used to simulate two different SZP configurations: a xenon gas-puff liner (SZP1*) and a silver solid liner (SZP2). The SZP2 results are compared against previously published MACH2 results, and a new code-to-code comparison on SZP1* is presented. Using an ideal equation of state and analytical transport coefficients, FLASH yields a fuel convergence ratio (CR) of approximately 39 and a mass-averaged fuel ion temperature slightly below 1 keV for the SZP2 scheme, significantly lower than the full-physics MACH2 prediction. For the new SZP1* configuration, full-physics FLASH simulations furnish large and inherently unstable CRs (> 300), but achieve fuel ion temperatures of many keV. While MACH2 also predicts high temperatures, the fuel stagnates at a smaller CR. The integrated code-to-code comparison reveals how magnetic insulation, heat conduction, and radiation transport affect platform performance and the feasibility of the SZP concept.