Determination of a macro- to micro-scale progression leading to a magnetized plasma disruption
We report the observations of a plasma jet evolving through a macro- to micro-scale progression sequence. This leads to a fast magnetic reconnection that results in the jet breaking off from its originating electrode and forming a force-free state. A sausage-like pinching occurs first and squeezes an initially fat, short magnetized jet so that it becomes thin. The thin jet then becomes kink unstable. The lengthening of the jet by the kinking thins the jet even more since the kink is an incompressible instability. When the jet radius becomes comparable to the ion-skin depth, Hall and electron inertial physics become important and establish the environment for a fast magnetic reconnection. This fast reconnection occurs, disrupting the jet and establishing a force-free state. X-ray bursts and whistler waves, evidence of a magnetic reconnection, are observed when the plasma jet breaks off from the electrode. This experimentally observed sequence of successive thinning from pinching followed by kinking is reproduced in a three-dimensional ideal Magnetohydrodynamic (MHD) numerical simulation. The results of the experiment and the numerical simulation, together demonstrate a viable path from macro-scale MHD physics to micro-scale non-MHD physics where fast reconnection occurs.
© 2020 Published under license by AIP Publishing. Submitted: 26 November 2019; Accepted: 15 January 2020; Published Online: 12 February 2020. This material is based upon the work supported by the NSF/DOE Partnership in Plasma Science via the U.S. Department of Energy Office of Science, Office of Fusion Energy Sciences Award No. DE-FG02-04ER54755, by the USDOE ARPA-E Grant via Award No. DE-AR0000565, by the NSF Division of Atmospheric and Geospace Sciences via Award No. 1914599, and by the Air Force Office of Scientific Research via Award No. FA9550-11-1-0184.
Published - 1.5140348.pdf
Accepted Version - 2020-Byonghoon-sasuage-kink-PoP-final-accepted-version.pdf