Laboratory Astrophysics and Collimated Stellar Outflows: The Production of Radiatively Cooled Hypersonic Plasma Jets

TLDR

The jet formation scenario mirrors the purely hydrodynamic mechanism described by Cantó et al. for astrophysical jets. The study aims to generate highly supersonic plasma jets via conically convergent flows, assess scaling for numerical code verification, and explore astrophysical issues such as collimation, stability, and jet‑cloud interactions. Electrodynamic acceleration of plasma in a conical array of fine metallic wires creates convergent flows that stagnate on the axis, forming a standing conical shock that collimates the jet; scaling considerations and code verification are also addressed.

Abstract

We present the first results of astrophysically relevant experiments where highly supersonic plasma jets are generated via conically convergent flows. The convergent flows are created by electrodynamic acceleration of plasma in a conical array of fine metallic wires (a modification of the wire array Z-pinch). Stagnation of plasma flow on the axis of symmetry forms a standing conical shock effectively collimating the flow in the axial direction. This scenario is essentially similar to that discussed by Cantó and collaborators as a purely hydrodynamic mechanism for jet formation in astrophysical systems. Experiments using different materials (Al, Fe, and W) show that a highly supersonic (M ~ 20), well-collimated jet is generated when the radiative cooling rate of the plasma is significant. We discuss scaling issues for the experiments and their potential use for numerical code verification. The experiments also may allow direct exploration of astrophysically relevant issues such as collimation, stability, and jet-cloud interactions.