Increase in Ion Temperature by Slow Wave Heating in Magnetosphere Plasma Device RT-1

Abstract

Ion cyclotron range of frequencies (ICRF) heating with a frequency of a few MHz and an input power of 10 kW was applied for the first time, to the best of our knowledge, in a magnetosphere plasma device. An antenna was installed near the pole of a dipole field for slow-wave excitation. Further, a ∩-shaped antenna was implemented and characterized for efficient ion heating. Electron cyclotron heating with an input power of 8 kW sustained helium plasmas with a fill gas pressure of 3 mPa. ICRF heating was then superimposed onto the target plasma (H, D, and He). While the ICRF power was turned on, the increase in ion temperatures was observed for low-pressure helium plasmas. However, the temperature increase was not clearly observed for hydrogen and deuterium plasmas. We discuss the experimental results in terms of power absorption based on result calculated with the TASK/WF2 code.

Electro-optic probe measurements of electric fields in plasmas

“…This so-called magnetic beach heating 1 has been studied in various machines. [2][3][4]8,16,17 In demonstrations, this ion heating scheme was confirmed to increase the ion temperature.…”

“…In order to achieve a high ion-beta state, we have studied ICRF heating in the magnetosphere configuration. 16 The antenna excites a slow wave with left-handed polarization (slow L wave) at a frequency of a few MHz. The electromagnetic wave propagates along the magnetic fields from the high to low field sides.…”

“…9 The TASK/WF2 code was applied in the first study of magnetosphere configuration. 16 The present paper is restricted to electric field measurements in plasmas by the EO probe.…”

Cyclotron Electromagnetic Instabilities in a Laboratory Dipole Magnetospheric Plasma with bi-Kappa Distributions

“…The dipole confinement concept to simulate a magnetosphere in laboratory conditions was originally proposed by Hasegawa [1]. Presently, there are active experiments on the plasma creation, confinement and heating in devices such as Levitated Dipole eXperiment (LDX) [2,3] and Ring Trap 1 (RT-1) [4][5][6][7]. The RT-1 device is a laboratory dipole magnetosphere (LDM) created by a levitated superconducting ring magnet.…”

“…The first successful results on the ion-cyclotron resonance (ICR) heating with a frequency of a few MHz in RT-1 plasma were reported recently in Ref. [6]. Both the ECR and ICR plasma heating methods can produce high-energy electrons and ions, respectively, which imply anisotropic temperatures of the resonant particles, with transverse temperature T ⊥ (relative to the confining magnetic field) greater than the parallel temperature T || .…”