Formation of supersonic ion flow in magnetic mirror laboratory plasma

Zongmau Lee^1*, Eiichirou Kawamori¹

¹Institute of Space and Plasma Sciences, 國立成功大學, 台南市, Taiwan

* Presenter:Zongmau Lee, email:happyfat332@gmail.com

A supersonic ion flow having a charge double-layer (DL) structure has been discovered in our laboratory magnetic mirror plasma experiments as a Laval-nozzle shock phenomenon. The axial profile of the density and plasma potential had drastic jump while the supersonic ion flow passed the mirror point. We measured axial profiles of the flow velocity, plasma potential, and density by a movable Langmuir probe array and a movable Mach probe. We make a comparison of variation of these quantities along the magnetic field lines with those predicted by Bernoulli's relationship. Although the driver of the supersonic ion flow is unclear yet, the supersonic flow generation is considered to resemble a Laval-nozzle shock phenomenon. For obtaining detailed information, we plan to investigate necessary conditions for the flow generation in terms of the plasma conditions including intensity of plasma generation, ion species, magnetic configurations, and plasma density. In this presentation, we will show the experimental results and physical interpretations.

Keywords: supersonic flow, plasma, charge double-layer , magnetic mirror plasma, Bernoulli's relationship