Multi‐Channel Analyzer Investigations of Ion Flux at the Target Surface in Pilot‐PSI

Solomon, M. L.; Anita, V.; Costin, C.; Mihăilă, Ilarion; Popa, G.; Meiden, H. van der; Al, R.S.; Pol, M. van de; Rooij, G.J. van; Rapp, J.

doi:10.1002/ctpp.201010152

Cited by 4 publications

(2 citation statements)

References 6 publications

(7 reference statements)

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“…At target position, the magnetic confinement of the plasma can be considered rather weak, since the cyclotron frequency of H + ions is in the same range as their collision frequency, but this doesn't limit the validity of the results. Similar distributions were also obtained at higher magnetic fields, both in Magnum-PSI [3] as well as in Pilot-PSI [4]. Moreover, the radial gradient of the floating potential is larger for higher magnetic field strengths [3].…”

Section: Current Distribution To the Surface Of The Floating Targetsupporting

confidence: 78%

Tailoring the charged particle fluxes across the target surface of Magnum-PSI

Costin

Anita

Popa

et al. 2016

Plasma Sources Sci. Technol.

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Linear plasma generators are plasma devices designed to study fusion-relevant plasma-surface interactions. The first requirement for such devices is to operate with adjustable and well characterized plasma parameters. In the linear plasma device Magnum-PSI, the distribution of the charged particle flux across the target surface can be tailored by the target bias. The process is based on the radial inhomogeneity of the plasma column and it is evidenced by electrical measurements via a 2D multi-probe system installed as target. Typical results are reported for a hydrogen discharge operated at 125 A and confined by a magnetic field strength of 0.95 T in the middle of the coils. The probes were biased in the range of -80 to -30 V, while the floating potential of the target was about -35 V. The results were obtained in steady-state regime of Magnum-PSI, being time-averaged over any type of fluctuations. Depending on the relative value of the target bias voltage with respect to the local floating potential in the plasma column, the entire target surface can be exposed to ion or electron dominated flux, respectively, or it can be divided into two adjacent zones: one exposed to electron flux and the other to ion flux. As a consequence of this effect, a floating conductive surface that interacts with an inhomogeneous plasma is exposed to non-zero local currents despite its overall null current and it is subjected to internal current flows.

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Section: Current Distribution To the Surface Of The Floating Targetsupporting

confidence: 78%

Tailoring the charged particle fluxes across the target surface of Magnum-PSI

Costin

Anita

Popa

et al. 2016

Plasma Sources Sci. Technol.

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“…The plasma beam in Magnum-PSI has so far mainly been characterized using Thomson scattering (TS) [4] and optical emission spectroscopy (OES) while the target surface has been investigated using infra-red (IR) imaging and calorimetry [5]. However, it has been shown that in Pilot-PSI-the forerunner of Magnum-PSI-the plasma beam is characterized by a strong radial electric field [6,7] and radial current flows through the sample exposed to the plasma [7]. It is thus of interest to characterize those parameters in Magnum-PSI where the target is exposed in a diverging magnetic field region.…”

Section: Introductionmentioning

confidence: 99%

Cross-section analysis of the Magnum-PSI plasma beam using a 2D multi-probe system

Costin

Anita

Ghiorghiu

et al. 2014

Plasma Sources Sci. Technol.

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The linear plasma generator Magnum-PSI was designed for the study of plasma-surface interactions under relevant conditions of fusion devices. A key factor for such studies is the knowledge of a set of parameters that characterize the plasma interacting with the solid surface. This paper reports on the electrical diagnosis of the plasma beam in Magnum-PSI using a multi-probe system consisting of 64 probes arranged in a 2D square matrix. Cross-section distributions of floating potential and ion current intensity were registered for a hydrogen plasma beam under various discharge currents (80-175 A) and magnetic field strengths (0.47-1.41 T in the middle of the coils). Probe measurements revealed a high level of flexibility of plasma beam parameters with respect to the operating conditions.

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