Time-resolved tuned diode laser absorption spectroscopy of pulsed plasma

Adámek, Petr; T, H; Čada, Martin; Hubička, Zdeněk; Hippler, R.

doi:10.1088/1742-6596/511/1/012088

Cited by 1 publication

(1 citation statement)

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“…Density and plasma potential fluctuations are typically evaluated from the ion saturation current and floating potential, respectively, neglecting the influence of the electron temperature fluctuations. This approach is often questioned as the properties of the floating and plasma potential fluctuations appear to be significantly different [1][2][3][4][5]. Recently, ball-pen probes (BPPs) were found to be well-suited for routine measurements of the plasma potential in the edge plasma of fusion devices [3,5].…”

Section: Introductionmentioning

confidence: 99%

Comparison of fluctuations properties measured by Langmuir and ball-pen probes in the ISTTOK boundary plasma

Silva¹,

Adámek²,

Fernandes³

et al. 2014

Plasma Phys. Control. Fusion

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In this work, the fluctuations properties measured by Langmuir and ball-pen probes are compared, aiming at investigating the influence of temperature fluctuations on Langmuir probe measurements, including the cross-field turbulent particle flux. With this aim, a 5-pin probe was designed to estimate the radial particle transport due to fluctuations simultaneously using Langmuir and ball-pen probes. A considerable difference is observed in the amplitude of the floating potential fluctuations measured by the two types of probes, but not in statistical properties such as skewness. The turbulent particle flux was found to be roughly four times larger when measured with Langmuir probes. However, quantities such as the phase velocity of the fluctuations or the poloidal correlation lengths are not significantly different, as floating potential fluctuations measured by both types of probes are highly correlated and roughly in phase. Finally, it is suggested that ball-pen and emissive probes may underestimate the amplitude of the plasma potential fluctuations and therefore probe measurements must be carefully validated.

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