Controlled Generation of Bernstien-Greene-Kruskal Modes (Bgk Modes); Electron Phase-Space Holes, Triple-Layer in Laboratory Plasma Experiments
李宗懋1*, 河森 榮一郎1, 張云瑄1, 陳勁廷1, 張皓1
1Institute of Space and Plasma Sciences, 國立成功大學, 台南市, Taiwan
* presenting author:Zongmau Lee,
We present well-controlled generation methods of nonlinear large amplitude steady electrostatic (ES) waves, so-called Bernstei-Greene-Kruskal (BGK) modes in laboratory plasma experiment, together with a novel diagnostic tool of the electron phase-space. The first idea is utilization of the autoresonance mechanism for generation of electron external drive and oscillator, which adjusts is a synchronization between an external drive and an oscillator, which adjusts its amplitude to phase-lock with the external drive [W, Bertsch et al., Phys. Rev .Lett. 91, 265003 (2003)].In this experiment we observe generation of large amplitude ES waves with an electron hole by the novel diagnostic tool called fast voltage sweep Langmuir probe (FVSLP). The second BGK mode is a steady state strong shock with a triple-layer (ΔVs > Te/e, where ΔVs and Te are the potential jump at the shock and the electron temperature, respectively). From a measurement of the electron distribution function, we observe a hole-structure in the shock region as well. In the presentation, we discuss detail of the generation mechanisms of respective BGK modes. In addition, potential applications of these techniques will be mentioned.

Keywords: Bernstei-Greene-Kruskal (BGK) modes, Neutral Magnetized plasma experiment, fast voltage sweep Langmuir probe (FVSLP), triple-layer, steady state strong shock