Collisional power absorption near mode conversion surface in helicon plasmas

Kim, S H; Hwang, Y. S.

doi:10.1088/0741-3335/50/3/035007

Cited by 13 publications

(11 citation statements)

References 20 publications

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“…9,18 Based on a fluid model, Kim pointed out that in the bulk mode conversion, collisional dissipation plays an important role near the MCS. 19 When the collision is absent, dispersion curves of the helicon and the TG merge at the MCS. Finite dissipation makes the dispersion curves split and the MCS moves slightly toward a higher density region.…”

Section: Introductionmentioning

confidence: 99%

Is the bulk mode conversion important in high density helicon plasma?

et al. 2016

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In a high-density helicon plasma production process, a contribution of Trivelpiece-Gould (TG) wave for surface power deposition is widely accepted. The TG wave can be excited either due to an abrupt density gradient near the plasma edge (surface conversion) or due to linear mode conversion from the helicon wave in a density gradient in the bulk region (bulk mode conversion). By numerically solving the boundary value problem of linear coupling between the helicon and the TG waves in a background with density gradient, we show that the efficiency of the bulk mode conversion strongly depends on the dissipation included in the plasma, and the bulk mode conversion is important when the dissipation is small. Also, by performing FDTD simulation, we show the time evolution of energy flux associated with the helicon and the TG waves.

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Section: Introductionmentioning

confidence: 99%

Is the bulk mode conversion important in high density helicon plasma?

et al. 2016

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“…At the condition, physically, the two wave branches become mode-converted to each other and reflected so they cannot propagate above the density of the determinant-zero. The approximate confluence density can be represented as equation ( 4) [34],…”

Section: Dispersion and Propagationmentioning

confidence: 99%

Current drive by using lower hybrid fast wave in VEST

Kim,

Jo,

Wang

et al. 2024

Nucl. Fusion

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An efficient central or off-axis current drive is necessary for the steady-state operation of tokamak fusion reactors. The fast wave branch in the frequency range above two times the lower hybrid resonance frequency at high density, the so-called LHFW, could be such an efficient current drive scheme in high density and high temperature of reactor-grade tokamak plasmas. This is because it has a higher parallel wave electric field for efficient Landau damping, compared to the fast wave branches in other frequency ranges, and it can more deeply penetrate high density plasmas than the slow wave in the same frequency range. An experimental study has been carried out to confirm the feasibility, in collaboration with KAERI, SNU, KWU, and KAPRA, in VEST. The results show that plasma current can be driven by the fast electrons generated by the LHFW. The details are reported including the theoretical background and RF system as well as the experiment results.

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“…The concept of the MCS can explain the jump in the deposited power during mode conversion [20]. There are two wave branches in the solution of the helicon dispersion relation: one is the helicon wave and the other is the TG wave.…”

Section: Discharge Mode Conversionmentioning

confidence: 99%

“…Another unique phenomenon in helicon discharges is that the plasma density jumps at a certain power, accompanied by a change of discharge mode [17,18]. F F Chen thought this was due to the nonmonotonic variation of the plasma impedance [19], while S H Kin used the concept of the mode conversion surface (MCS) to explain the mode conversion [20]. In the field of helicon discharge simulation, D Arnush studied the coupling of helicon waves and TG waves using the HELIC software [21], and X Yang analyzed the phenomenon of the density peak in the weak magnetic field using the COMSOL software [22].…”

Section: Introductionmentioning

confidence: 99%

Simulation of a helicon plasma source in a magnetoplasma rocket engine

Yang¹,

Fan²,

Wei³

et al. 2022

Plasma Sci. Technol.

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The helicon plasma source is of vital importance for the magnetoplasma rocket engine (MPRE) to generate high thrust and high impulse. In this paper, a multi-component, two-dimensional, axisymmetric fluid model coupled with electromagnetic field was developed to model the helicon discharge. The simulation results demonstrate that, the discharge mode converts two times and each conversion is accompanied with a plasma density jump and an electron temperature peak in the discharge; the plasma density increases with the input current and the ionization becomes faster; the background magnetic field has an obvious enhancement to the discharge but the plasma density may be smaller if the discharge hasn’t entered into wave mode.

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Collisional power absorption near mode conversion surface in helicon plasmas

Cited by 13 publications

References 20 publications

Is the bulk mode conversion important in high density helicon plasma?

Is the bulk mode conversion important in high density helicon plasma?

Current drive by using lower hybrid fast wave in VEST

Simulation of a helicon plasma source in a magnetoplasma rocket engine

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