# Experimental Study of Ion Heating in Obliquely Merging Hypersonic Plasma Jets

## TL;DR

This experimental study investigates ion heating in obliquely merging hypersonic plasma jets, revealing classical ion shock heating behavior, ion-electron equilibration, and implications for plasma-jet-driven fusion applications.

## Contribution

It provides new experimental data on ion temperature evolution and shock heating in colliding plasma jets across various species and conditions, relevant to fusion technology.

## Key findings

- Ion shock heating is nearly classical and consistent with collisional models.
- Ion-electron temperature equilibration occurs during shock formation.
- Reduced density gradients and jet interpenetration may benefit fusion applications.

## Abstract

In this experiment, we measure ion temperature evolution of collisional plasma shocks and colliding supersonic plasma flows across a range of species (Ar, Kr, Xe, N), Mach numbers, and collisionalities. Shocks are formed via the collision of discrete plasma jets relevant to plasma-jet-driven magneto-inertial fusion (PJMIF). We observe nearly classical ion shock heating and ion-electron equilibration, with peak temperatures attained consistent with collisional shock heating. We also observe cases where this heating occurs in a smooth merged structure with reduced density gradients due to significant intepenetration of the plasma jets. In application to PJMIF liners, we find that Mach number degradation due to ion shock heating will likely not be significant at the typical full-scale conditions proposed, and that a degree of interpenetration may be an attractive condition for PJMIF and similar approaches which seek to form uniform merged structures from discrete supersonic plasma jets.