Observation of spatiotemporal structures of temperature fluctuations by using of a statistical phase detection method in a linear magnetized plasma

Abstract

In this paper, we evaluated electron temperature fluctuations by using a conditional sampling and a statistical phase detection method. These methods allow us to reconstruct probe I − V characteristics at each time delay; that is, we can extract electron temperature and ion saturation current fluctuations in high temporal resolution without complex electronic circuits. Our method was applied to two quasi-coherent fluctuations observed in a linear magnetized plasma device, PANTA. We observed spatiotemporal structures of electron temperature and ion saturation current fluctuations. The results revealed the amplitudes and phase relation between electron temperature and density fluctuations.

Transition between continuous and discrete spectra of high-wavenumber turbulence in neutral gas pressure scan experiments on a linear magnetized plasma

“…Note that the difference in P n makes little difference to the RF absorbed power into the plasma. Compared to the plasma profiles in the conventional drift wave studies on the PANTA [36][37][38][39], the density is an order of magnitude smaller while the temperature and the gradients of density and temperature are about the same order. The density, temperature, and gradients seem to be larger for the lower P n condition.…”

“…Recently, the experiment which aims at the detailed observation of high-wavenumber turbulence has been established under the partially ionized condition in the PANTA [35]. In the experiment, by creating a partially magnetized plasma state through magnetic field control, we succeeded in observing high-wavenumber turbulence on a smaller scale than the ion-scale drift wave turbulence that has been studied well [36][37][38][39]. In this paper, we present experimental observations of transition phenomena in neutral Argon gas pressure scan experiments.…”

Joint meeting of 9th Asia Pacific-Transport Working Group (APTWG) & EU-US Transport Task Force (TTF) workshop

“…Kawachi reported a recent experimental study of the dynamic interactions of different modes in the linear device, PANTA. Employing a movable azimuthal probe array, detailed measurements were carried out for a plasma in which different types of fluctuations are excited [42]. Two different modes were identified by measuring the poloidal and toroidal mode number (m,n) of the fluctuations: 1) an axially symmetric (AS) flute like mode with (m,n)=(1,0) and 2) a resistive drift wave (DW) with (m,n)=(4,1 2).…”