Experimental characterization of the stagnation layer between two obliquely merging supersonic plasma jets

TL;DR

This paper provides detailed spatial measurements of the stagnation layer between two supersonic plasma jets merging at an angle, revealing features consistent with collisional oblique shocks in a high-collisionality plasma environment.

Contribution

It offers the first spatially resolved characterization of the stagnation layer in obliquely merging supersonic plasma jets, highlighting the role of collisional shocks.

Findings

Double-peaked emission profile observed in the stagnation layer.

Central emission dip correlates with a density dip.

Inter-jet ion-ion mean free paths are comparable to the layer thickness.

Abstract

We present spatially resolved measurements characterizing the stagnation layer between two obliquely merging supersonic plasma jets. Intra-jet collisionality is very high ($\lambda_{ii} \ll 1$mm), but the inter-jet ion-ion mean free paths are on the same order as the stagnation layer thickness (a few cm). Fast-framing camera images show a double-peaked emission profile transverse to the stagnation layer, with the central emission dip consistent with a density dip observed in the interferometer data. We demonstrate that our observations are consistent with collisional oblique shocks.