Experimental Studies of Magnetically Driven Plasma Jets

TL;DR

This paper reports experimental creation of magnetically driven plasma jets that mimic astrophysical jets in morphology and dynamics, providing insights into jet formation, collimation, and variability.

Contribution

It introduces a novel experimental setup that replicates key features of astrophysical jets, including magnetic collimation and episodic behavior, enabling scaled laboratory studies.

Findings

Jets have Mach number, plasma beta, and cooling similar to protostellar jets.

Reynolds and magnetic Reynolds numbers are much larger than unity, supporting astrophysical scaling.

Preliminary energy and magnetic field measurements suggest conditions comparable to astrophysical environments.

Abstract

We present experimental results on the formation of supersonic, radiatively cooled jets driven by pressure due to the toroidal magnetic field generated by the 1.5 MA, 250 ns current from the MAGPIE generator. The morphology of the jet produced in the experiments is relevant to astrophysical jet scenarios in which a jet on the axis of a magnetic cavity is collimated by a toroidal magnetic field as it expands into the ambient medium. The jets in the experiments have similar Mach number, plasma beta and cooling parameter to those in protostellar jets. Additionally the Reynolds, magnetic Reynolds and Peclet numbers are much larger than unity, allowing the experiments to be scaled to astrophysical flows. The experimental configuration allows for the generation of episodic magnetic cavities, suggesting that periodic fluctuations near the source may be responsible for some of the variability observed in astrophysical jets. Preliminary measurements of kinetic, magnetic and Poynting energy of the jets in our experiments are presented and discussed, together with estimates of their temperature and trapped toroidal magnetic field.