Ion flow measurements and plasma current analysis in the Irvine Field Reversed Configuration

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• Trask, E.
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• Roche, T.
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• Garate, E. P.
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• Heidbrink, W. W.
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• McWilliams, R.

Abstract

Measurements of the Doppler shift of impurity lines indicate that there is an ion flow of ∼7 km/s in the Irvine Field Reversed Configuration. A charge-exchange neutral particle analyzer shows the peak energy is below the 20 eV minimum detectable energy threshold, which is in agreement with the spectroscopic data. By evaluating the collision times between the impurities and hydrogen, the dominant plasma ion species, it is concluded that the ions rotate with an angular frequency of ∼4×10⁴ rad/s. Estimates of the ion current in the laboratory frame indicate it is one to two orders of magnitude larger than the measured plasma current of 15 kA. Electron drifts are expected to cancel most of the ion current based on the measured magnetic fields and calculated electric fields.