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

Qin, Chengming; Zhang, Xinjun; Zhao, Yanping; Wan, Baonian; Braun, F.; Wang, Lei; Yang, Qingxi; Yuan, Shuai; Cheng, Yan; East, Icrf team on

doi:10.1088/1009-0630/17/2/12

Cited by 21 publications

(15 citation statements)

References 23 publications

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“…The coupling resistance R c in equation 1is the same order of the coupling efficiency κ. So we expect that R c as a function of the k // or L c also obeys the equation (6) approximately. The cutoff density of the plasma is calculated by solving the equation: , minority hydrogen concentration is around 5-7%.…”

Section: Resultsmentioning

confidence: 89%

“…The newly designed and installed ICRF antenna in I port aiming at increasing the ICRF heating efficiency has been analyzed theoretically in Ref. [6]. The ICRF antenna array which consists of 4 straps can operate in various heating and current drive phasing cases in 25~70MHz.…”

Section: Introductionmentioning

confidence: 99%

“…Widening the gap is equivalent to increase the evanescent layer width between the antenna straps and the position of the cutoff density without changing plasma density profile. Furthermore, the coupling efficiency decreases with the gap increasing as an exponential function according to the equation(6).…”

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confidence: 99%

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Experimental analysis of the ICRF waves coupling in EAST

et al. 2017

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The experiments were carried out to study the coupling characteristics of the I-port antenna in the ion cyclotron range of frequencies (ICRF) in EAST. The dependencies of the coupling resistance on various parameters including the antenna position, the central electron density, gas injection and the antenna phasing have been studied. The results obtained show that the experimental data are consistent with theoretical simulations. We find that the antenna loading resistance decreases sharply at the L-H transition due to the change of the plasma density profiles in the scrape-off layer (SOL). The effect of the low hybrid wave (LHW) on the ICRF coupling during the H-mode is observed. The theoretical interpretation of the results is discussed, together with the efficient methods to optimize the coupling efficiency.

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Section: Resultsmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

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Experimental analysis of the ICRF waves coupling in EAST

et al. 2017

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“…In tokamaks such as EAST, the electron plasma frequency

ω_{italicpe} = \sqrt{n_{e, 0} e^{2} / m_{e} ϵ_{0}}

is about 10 3 − 10 4 MHz for the typical edge plasma density 10 17 < n 0 < 10 18 m −3 , and the applied ICRF during ICRF wave heating is in the range of 25 MHz < ω < 72 MHz . [ 21 ] Therefore, the electrons can respond to the instantaneous sheath potential as ω ≪ ω pe . Integrating the electron distribution function in a sheath over the velocity space gives the electron density in the sheath as follows [ 20 ]

n_{e} false(x, t false) = n_{e 0} {([], 1 - \frac{italiceϕ (x, t)}{(κ - 3 false/ 2) k_{B} T_{e}})}^{- κ + 1 / 2},

and the electron flux at the wall is

J_{e} = n_{e, 0} \sqrt{\frac{(κ - 3 false/ 2) T_{e}}{2 π m_{e}}} \frac{Γ false(κ - 1 false)}{Γ false(κ - 1 / 2 false)} {([], 1 - \frac{e ϕ_{w}}{(κ - 3 false/ 2) k_{B} T_{e}})}^{1 - κ}

…”

Section: Model Descriptionmentioning

confidence: 99%

Ion energy distribution in a radio frequency sheath of plasma with Kappa electron velocity distribution

Huang

2020

Contributions to Plasma Physics

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A hybrid model consisting of a one-dimensional radio frequency sheath model and an equivalent circuit model is used to investigate the effect of the non-Maxwellian plasma with enhanced electron tails on ion energy distribution (IED) at the plasma-wall interface. With the assumption that electrons obey the Kappa distribution in which the parameter κ characterizes the deviation from Maxwellian distribution, the bimodal shape of the IED can always be found with the decrease of κ under the condition of current experimental advanced superconducting tokamak (EAST) discharges during the ion cyclotron range of frequency wave heating. However, the height of the low-energy peak of the IED decreases, while the high-energy peak does not change significantly. In addition, the IED shifts towards the higher-energy regime, and the width of the IED expands with the decrease of κ. It is also shown that frequency and amplitude of the disturbance current, bulk plasma density, and ion temperature are the crucial parameters for determining the shape of IED even in the presence of super-thermal electrons.

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“…In this letter we report the first direct observation of enhanced plasma potential due to unabsorbed fast wave in the ICRF heated discharges on EAST. EAST ICRF system has a two by two strap antenna located in the B port and a four strap antenna in the I port [13]. All the antenna are operated in a phasing and frequency to heat a H minority in D plasma [2].…”

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Experimental observation of enhanced plasma potential due to unabsorbed fast wave on EAST

et al. 2019

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An experiment on EAST is used to study the fast wave rectification by only an actively powered I-port antenna. The plasma potential up to 100V was found in the region that do not map along magnetic field line to active I-port antenna. This enhancement correlates with the local fast wave intensity. An increase in the loading resistance and heating efficiency was observed at low parallel wave number. The higher heating efficiency is seen to cause lower unabsorbed fast wave power in the SOL regions. This can cause a decrease in fast wave field intensity that reaches plasma facing components and can result in decrease in the plasma potential and slow wave intensity.

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

Cited by 21 publications

References 23 publications

Experimental analysis of the ICRF waves coupling in EAST

Experimental analysis of the ICRF waves coupling in EAST

Ion energy distribution in a radio frequency sheath of plasma with Kappa electron velocity distribution

Experimental observation of enhanced plasma potential due to unabsorbed fast wave on EAST

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