Experimental investigation of the potentials modified by radio frequency sheaths during ion cyclotron range of frequency on EAST

Qin, Chengming; Zhao, Yubo; QWang, H.; Zhang, X. J.; Wan, B. N.; Noterdaeme, Jean-Marie; Braun, F.; Bobkov, V.; Kasahara, Hiroshi; Kong, E. H.; Wang, L.; Yuan, Shuai; He, Zhixiong; Ding, Bojiang; Team, Icrf; Team, East

doi:10.1088/0741-3335/55/1/015004

Cited by 22 publications

(16 citation statements)

References 21 publications

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“…V DC was also inferred from variations of the Langmuir probe floating potential V f , e.g. in [10,[20][21][22][23][24][25][26][27]. Interpreting the floating potentials might however be ambiguous: although V f is related to DC plasma biasing, it is rather indicative of DC currents collected by the grounded probe (see paragraph 2.6).…”

Section: Sol DC Biasing Due To Rf Sheath Rectificationmentioning

confidence: 99%

The geometry of the ICRF-induced wave–SOL interaction. A multi-machine experimental review in view of the ITER operation

Colas¹,

Urbanczyk²,

Goniche³

et al. 2021

Nucl. Fusion

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As part of ITPA-Integrated Operational Scenario activities, this contribution reviews recent experimental characterizations of radio-frequency (RF)-induced scrape-off layer (SOL) modifications of various tokamaks worldwide and of the LArge Plasma Device at UCLA. The phenomenology, as observed using a large variety of measurement techniques, is consistent with expectations from RF sheath rectification. Emphasis is then put on the complex three-dimensional (3D) spatial patterns of the RF–SOL interaction, in relation to the magnetic topology and the spatial distribution of RF currents over the metallic structures surrounding the RF wave launchers. Dependence on the local plasma parameters in the antenna vicinity is also briefly addressed. The final part discusses implications for future devices.

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Section: Sol DC Biasing Due To Rf Sheath Rectificationmentioning

confidence: 99%

The geometry of the ICRF-induced wave–SOL interaction. A multi-machine experimental review in view of the ITER operation

Colas¹,

Urbanczyk²,

Goniche³

et al. 2021

Nucl. Fusion

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“…As discussed in the introduction, this contributes to reduced heating efficiency, hot spots on the antenna and near-by limiters, and enhanced sputtering, SOL electric fields and plasma convection. [4][5][6][7][8][9][10][11][12][13] In addition to modeling the sputtering energies available to ions that have been accelerated through the sheath, an important application of the rf sheath model is to understand power dissipation.…”

Section: Sheath Power Dissipationmentioning

confidence: 99%

Radio frequency sheaths in an oblique magnetic field

Myra

D’Ippolito

2015

Physics of Plasmas

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The physics of radio-frequency (rf) sheaths near a conducting surface is studied for plasmas immersed in a magnetic field that makes an oblique angle with the surface. A set of one-dimensional equations is developed that describe the dynamics of the time-dependent magnetic presheath and non-neutral Debye sheath. The model employs Maxwell-Boltzmann electrons, and the magnetization and mobility of the ions is determined by the magnetic field strength, and wave frequency, respectively. The angle , assumed to be large enough to insure an electron-poor sheath, is otherwise arbitrary. Concentrating on the ion-cyclotron range of frequencies, the equations are solved numerically to obtain the rectified (dc) voltage, the rf voltage across the sheath and the rf current flowing through the sheath. As an application of this model, the sheath voltage-current relation is used to obtain the rf sheath impedance, which in turn gives an rf sheath boundary condition for the electric field at the sheath-plasma interface that can be used in rf wave codes. In general the impedance has both resistive and capacitive contributions, and generalizes previous sheath boundary condition models. The resistive part contributes to parasitic power dissipation at the wall.

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“…The plane is 1 cm in front of the antenna Faraday Screen (FS). In order to compare the performances of the new 4-strap antenna and the original 2-strap antenna on EAST [14] , their simplified models are shown in Fig. 1(b) and (c), respectively.…”

Section: Antenna Modeling 21 Basic Description Of the Antenna Modelmentioning

confidence: 99%

Electromagnetic Analysis of the EAST 4-Strap ICRF Antenna with HFSS Code

Qin

Zhang

Zhao

et al. 2015

Plasma Sci. Technol.

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A new ICRF antenna has been designed in EAST, whose aims are to reduce the parallel RF electric fields E and to investigate the current drive using the fast magnetosonic wave. This antenna consists of four toroidally spaced radiating straps. The electrical characteristics of the new antenna are estimated by using a three-dimensional electromagnetic commercial code. The S-parameters, RF current distribution and electromagnetic field distribution on and near the 4-strap antenna are analyzed, and the RF potentials influenced by antenna phasing and radial position are investigated.

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Experimental investigation of the potentials modified by radio frequency sheaths during ion cyclotron range of frequency on EAST

Cited by 22 publications

References 21 publications

The geometry of the ICRF-induced wave–SOL interaction. A multi-machine experimental review in view of the ITER operation

The geometry of the ICRF-induced wave–SOL interaction. A multi-machine experimental review in view of the ITER operation

Radio frequency sheaths in an oblique magnetic field

Electromagnetic Analysis of the EAST 4-Strap ICRF Antenna with HFSS Code

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