One-dimensional radiation-hydrodynamic scaling studies of imploding spherical plasma liners

TL;DR

This study uses one-dimensional radiation-hydrodynamic simulations to analyze how initial conditions affect the stagnation pressure in imploding spherical plasma liners, revealing key scaling laws and the importance of radiation transport.

Contribution

It provides new scaling laws for stagnation pressure and lifetime of plasma liners, emphasizing the role of radiation transport and thermal conduction in simulations.

Findings

Peak pressures near 1 Mbar achievable with several hundred kJ energy liners.

Stagnation pressure scales approximately as v0^(15/4) and n0^(1/2).

Stagnation lifetime scales with initial liner thickness and velocity.

Abstract

One-dimensional radiation-hydrodynamic simulations are performed to develop insight into the scaling of stagnation pressure with initial conditions of an imploding spherical plasma shell or "liner." Simulations reveal the evolution of high-Mach-number (M), annular, spherical plasma flows during convergence, stagnation, shock formation, and disassembly, and indicate that cm- and {\mu}s-scale plasmas with peak pressures near 1 Mbar can be generated by liners with initial kinetic energy of several hundred kilo-joules. It is shown that radiation transport and thermal conduction must be included to avoid non-physical plasma temperatures at the origin which artificially limit liner convergence and thus the peak stagnation pressure. Scalings of the stagnated plasma lifetime ({\tau}stag) and average stagnation pressure (Pstag, the pressure at the origin, averaged over {\tau}stag) are determined by evaluating a wide range of liner initial conditions. For high-M flows, {\tau}stag L0/v0, where L0 and v0 are the initial liner thickness and velocity, respectively. Furthermore, for argon liners, Pstag scales approximately as v0^(15/4) over a wide range of initial densities (n0), and as n0^(1/2) over a wide range of v0. The approximate scaling Pstag ~ M 3/2 is also found for a wide range of liner-plasma initial conditions.