Transverse motion of a plasma column in a sheet plasma

Abstract

In this paper, we show the dynamic behaviors of a sheet plasma and the corresponding release of blob-like plasmas to the periphery of the sheet based on observation with a high-speed camera. We found that the plasma column moves in a transverse direction reciprocally when injecting a small amount of Ar gas to the He plasma from the plasma source region. The motion continued periodically at a frequency of ∼5 kHz. The frequency of the plasma column motion decreased with increasing Ar gas flow rate and increasing magnetic field. The mechanism of the transverse motion is discussed. Furthermore, in response to the reciprocating motion, release of a blob-like plasma was observed. The differences in the behavior of the released plasma compared with the other linear devices are discussed. KEYWORDS linear device, plasma dynamics, sheet plasma 1 How to cite this article: Onda T, Kajita S, Iijima T, Tonegawa A, Ohno N and Tanaka H. Transverse motion of a plasma column in a sheet plasma. Contrib. Plasma Phys.

Mode Structure Analysis of Detached Plasmas with 2D Images

“…Figure 6 (b) shows the temporal evolution of wavelet spectrum. Previously, blob-like phenomena were observed in a similar linear device TPD-Sheet IV [6], where the blowoffs occur periodically. Different from TPD-Sheet IV, the phenomena were intermittent in NAGDIS-II.…”

“…Plasma blob has a filamentary structure along the magnetic field line and has a higher density than the SOL plasma. Interestingly, the cross-filed plasma transport, which could be associated with plasma blob-like structure, was found to be enhanced in the detached plasma condition in linear plasma devices [4][5][6], helical devices [7], and tokamaks [8,9]. In the linear plasma device NAGDIS-II (NAGoya DIvertor plasma Simulator II), fast framing camera observations have revealed that a spiral structure ejected from the plasma column was rotated in E × B direction in the peripheral region of the plasma column, where the electric field was in the radial direction [4,10].…”

Study of the intermittent plasma structure around the divertor simulation experimental module in GAMMA 10/PDX

“…In magnetic confinement fusion devices, plasma detachment based on the interaction between the plasma and neutral particles is a promising way to reduce the heat load on the divertor plate. In the detached divertor condition, an enhancement of the cross-field plasma transport is observed in several magnetic confinement devices including torus [1,2,3,4,5] and linear plasma devices [6,7,8,9,10,11]. In linear device NAGDIS-II, the enhanced transport was found to be generated locally along the magnetic field lines [12,9], and the region was identified to be near the highly volume-recombining region, called the "recombination front" [13].…”

Structure of intermittent variation of floating potential in a converging field following a magnetic beach ECR plasma source

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