Extreme hydrogen plasma densities achieved in a linear plasma generator

Rooij, G.J. van; Veremiyenko, V.P.; Goedheer, W. J.; Groot, B. de; Kleyn, A.W.; Smeets, P.H.M.; Versloot, T. W.; Whyte, D.G.; Engeln, Rah Richard; Schram, D.C.; Cardozo, N.J. Lopes

doi:10.1063/1.2716208

Cited by 147 publications

(97 citation statements)

References 13 publications

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“…This yielded unprecedented plasma fluxes and densities by virtue of a synergetic action of high magnetic fields and an optimized nozzle geometry. 11 However, the total plasma flux was still an order of magnitude lower than what is required for Magnum-PSI. In this paper, we investigate how the plasma production can be improved by a factor of 10 over what the flux is in the operational conditions of Ref.…”

Section: A Motivationmentioning

confidence: 95%

Optimization of the output and efficiency of a high power cascaded arc hydrogen plasma source

et al. 2008

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The operation of a cascaded arc hydrogen plasma source was experimentally investigated to provide an empirical basis for the scaling of this source to higher plasma fluxes and efficiencies. The flux and efficiency were determined as a function of the input power, discharge channel diameter, and hydrogen gas flow rate. Measurements of the pressure in the arc channel show that the flow is well described by Poiseuille flow and that the effective heavy particle temperature is approximately 0.8 eV. Interpretation of the measured I -V data in terms of a one-parameter model shows that the plasma production is proportional to the input power, to the square root of the hydrogen flow rate, and is independent of the channel diameter. The observed scaling shows that the dominant power loss mechanism inside the arc channel is one that scales with the effective volume of the plasma in the discharge channel. Measurements on the plasma output with Thomson scattering confirm the linear dependence of the plasma production on the input power. Extrapolation of these results shows that ͑without a magnetic field͒ an improvement in the plasma production by a factor of 10 over where it was in van Rooij et al. ͓Appl. Phys. Lett. 90, 121501 ͑2007͔͒ should be possible.

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Section: A Motivationmentioning

confidence: 95%

Optimization of the output and efficiency of a high power cascaded arc hydrogen plasma source

et al. 2008

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“…Pilot-PSI is a high-density (n e =0.1-10x10 20 m -3 ), high-flux (>10 23 m -2 s -1 ) linear plasma generator [6] that operates in an axial magnetic field (0.4-1.6T). While intense, the plasma column generated is also quite narrow with a typical ion flux full-width-half-maximum of ~10 [7] is a program that simulates ion beam analysis spectra.…”

Section: Pilot-psi Exposuresmentioning

confidence: 99%

Comparison of tungsten nano-tendrils grown in Alcator C-Mod and linear plasma devices

Wright¹,

Brunner²,

Baldwin³

et al. 2013

Journal of Nuclear Materials

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Abstract:Growth of tungsten nano-tendrils ("fuzz") has been observed for the first time in the divertor region of a high-power density tokamak experiment. After 14 consecutive helium L-mode discharges in Alcator C-Mod, the tip of a tungsten Langmuir probe at the outer strike point was fully covered with a layer of nano-tendrils. The depth of the W fuzz layer (600 ± 150 nm) is consistent with an empirical growth formula from the PISCES experiment. Re-creating the C-Mod exposures as closely as possible in Pilot-PSI experiment can produce nearly-identical nano-tendril morphology and layer thickness at surface temperatures that agree with uncertainties with the C-Mod W probe temperature data. Helium concentrations in W fuzz layers are measured at 1-4 at.%, which is lower than expected for the observed sub-surface voids to be filled with several GPa of helium pressure. This possibly indicates that the void formation is not pressure driven.

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“…The predamaged tungsten targets were exposed to intense deuterium plasma beams at the linear plasma generator Pilot-PSI [11]. The plasma was created by a cascaded arc source and transported to the target by an axial magnetic field of 0.4 T. During the exposures, the targets were water cooled and electrically floating.…”

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confidence: 99%