Characteristics of the high density plasma production by <i>m</i>=0 helicon wave

Sakawa, Y.; Koshikawa, N.; Shoji, T.

doi:10.1063/1.118001

Cited by 31 publications

(32 citation statements)

References 3 publications

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“…Very few experimental investigations were conducted to find an optimum B 0 in helicon wave discharges using molecular gases such as H 2 and N 2 . 14 In this article, we investigate the contribution of the SW on high-density plasma production by mϭ0 helicon waves 14,[16][17][18][19][20] using several gases such as H 2 , D 2 , He, N 2 , Ne, Ar, and Xe.…”

Section: Introductionmentioning

confidence: 99%

Contribution of slow waves on production of high-density plasmas by m=0 helicon waves

1999

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Towards a better comprehension of plasma formation and heating in high performances electron cyclotron resonance ion sources (invited) Rev. Sci. Instrum. 83, 02A336 (2012) Commissioning of heating neutral beams for COMPASS-D tokamak Rev. Sci. Instrum. 83, 02B114 (2012) Development of a versatile multiaperture negative ion source Rev. Sci. Instrum. 83, 02A707 (2012) Plasma dynamics in microsecond megaampere plasma opening switchesThe contribution of the slow waves ͑SWs͒ on high-density plasma production by mϭ0 helicon waves is investigated in H 2 , D 2 , He, N 2 , Ne, Ar, and Xe plasmas. The density-jump is observed in all the gases used at optimum external magnetic fields B 0 . The measured plasma density n p as a function of B 0 peaks at a condition close to the lower-hybrid resonance in H 2 , D 2 , He, N 2 , and Ne, whereas, the measured dispersion relation indicates the excitation of helicon wave. Dispersion relation of electromagnetic waves is solved using dielectric tensor elements of a cold uniform plasma including ion terms, which shows two branches: the SW and fast ͑helicon͒ wave. The transition from the ionization by SWs, which are excited in the low-density plasma produced by an antenna induction field, to that by helicon waves has been predicted to explain the mechanism to produce the high-density plasma in the helicon wave discharges.

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Section: Introductionmentioning

confidence: 99%

Contribution of slow waves on production of high-density plasmas by m=0 helicon waves

1999

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“…Differing experimental conditions could also lead to disparities in the results. For instance, the helicon waves were often generated in a small tube and then injected into a larger chamber [5,6,8,9], thus violating boundary conditions used in existing theories. In some cases, a fullwavelength antenna was used instead of a half-wavelength antenna [5,6]; a light ion was used instead of argon [9]; or the magnetic field was extremely uniform [7].…”

Section: Introductionmentioning

confidence: 99%

Helicon wave excitation with rotating antenna fields

Miljak

Chen

1998

Plasma Sources Sci. Technol.

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By using phased bifilar antennas, helicon waves have been excited by applying fields which rotate either in space or in time, or both simultaneously. The direction of rotation is made to favor either m = +1 or m = -1 waves, where m is the azimuthal mode number, and m is measured directly. Rotation in time is found to be more effective than rotation in space and makes possible a direct comparison of m = ±1 excitation. An m = -1 structure was seen only in the antenna near-field, while m = +1 modes propagate far downstream. Up to 2 kW of RF power, density profiles and antenna loading measurements show that m < 0 (left-hand) waves are poorly coupled, and m = +1 (right-hand) waves are necessary for good plasma production. Loading results indicate that antennas also couple to absorption mechanisms unrelated to helicon waves.

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“…This extrapolation is highly conjectural and is based on the belief that proper gas handling will overcome the problems encountered in the present experiment. Sakawa et al have achieved densities >10 14 cm −3 in a geometry [21] similar to that proposed in figure 13, but the experiment was not pushed to the 10 15 cm −3 densities envisioned here.…”

Section: Conclusion and Projectionsmentioning

confidence: 61%

“…Equating (9) and (10), we find that n n cannot be found this way, while n e is given by n e =v/2aP i f…”

Section: Conclusion and Projectionsmentioning

confidence: 99%