Experimental study of ion heating in obliquely merging hypersonic plasma jets

In this study, we measure ion temperature evolution of collisional plasma shocks and colliding supersonic plasma flows across a range of species (Ar, Kr, Xe, and 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. Additionally, we 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.