Plasma and Fusion Research

Volume 14, 1201046 (2019)

Rapid Communications

A Single-Shot Method for Measuring the Energy Spectra of Pure Electron Plasmas Driven by E × B Rotation
Youngsoo PARK, Yukihiro SOGA, Masayuki SATO, Nozomi SUZUTANI1) and Takashi KIKUCHI1)
Kanazawa University, Kanazawa 920-1192, Japan
1)
Nagaoka University of Technology, Nagaoka 940-2188, Japan
(Received 9 January 2019 / Accepted 29 January 2019 / Published 25 February 2019)

Abstract

In this study, a new single-shot method is developed for obtaining the parallel energy spectra of pure electron plasmas that rotate around the machine axis by the E × B drift. When the confinement voltage is raised to the ground level on a timescale that is comparable with the E × B rotation period, the electrons escape from the confinement region along the magnetic field lines over the potential barrier and onto a phosphor screen in the descending order of the energy of the electrons. This causes the phosphors to emit light at different points on the screen along the E × B rotation trajectory depending on the electron's energies. Further, the energy distribution can be derived from the luminosity distribution along this trajectory by appropriately converting these positions into their corresponding energy levels.

Keywords

nonneutral plasma, E × B drift rotation, edge-dependent drift, parallel energy analysis

DOI: 10.1585/pfr.14.1201046

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