Development of miniaturized, spectroscopically assisted Penning gauges for fractional helium and hydrogen neutral pressure measurements

Flesch, Kurt; Kremeyer, T.; Schmitz, O.; Soukhanovskii, Vlad; Wenzel, U.

doi:10.1063/1.4960815

Cited by 6 publications

(3 citation statements)

References 11 publications

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“…Three, for optical spectroscopy optimized Penning gauges [24], have been mounted in the divertor pumping gaps and the midplane of one module. The Penning discharge, with an anode potential of 2 kV, is observed with a set of high temperature, ultra-high vacuum optics and analyzed by the filterscope system (section 4.8).…”

Section: Neutral Pressure Gaugesmentioning

confidence: 99%

Upgrades of edge, divertor and scrape-off layer diagnostics of W7‐X for OP1.2

Hathiramani

Ali

Anda

et al. 2018

Fusion Engineering and Design

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Wendelstein 7-X (W7-X) is the world's largest superconducting nuclear fusion experiment of the optimized stellarator type. In the first Operation Phase (OP1.1) helium and hydrogen plasmas were studied in limiter configuration. The heating energy was limited to 4 MJ and the main purpose of that campaign was the integral commissioning of the machine and diagnostics, which was achieved very successfully. Already from the beginning a comprehensive set of diagnostics was available to study the plasma. On the path towards high-power, high-performance plasmas, W7-X will be stepwise upgraded from an inertially cooled (OP1.2, limited to 80 MJ) to an actively cooled island divertor (OP2, 10 MW steady-state plasma operation). The machine is prepared for OP1.2 with 10 inertially cooled divertor units, and the experimental campaign has started recently.The paper describes a subset of diagnostics which will be available for OP1.2 to study the plasma edge, divertor and scrape-off layer physics including those already available for OP1.1, plus modifications, upgrades and new systems. The focus of this summary will be on technical and engineering aspects, like feasibility and assembly but also on reliability, thermal loads and shielding against magnetic fields.

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Section: Neutral Pressure Gaugesmentioning

confidence: 99%

Upgrades of edge, divertor and scrape-off layer diagnostics of W7‐X for OP1.2

Hathiramani

Ali

Anda

et al. 2018

Fusion Engineering and Design

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“…This allows the diagnostic to be mounted close to the plasma or inside of the divertor baffle. Several anode geometries were tested to allow for an optimized optical observation of the discharge in the Penning cell, while remaining a reliable total pressure measurement [6]. Figure 7 shows the design of the Penning probe head that was selected for W7-X.…”

Section: Penning Gaugesmentioning

confidence: 99%

Advanced neutral gas diagnostics for magnetic confinement devices

et al. 2017

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For the study of particle exhaust in nuclear fusion devices the neutral pressure must be measured in strong magnetic fields. We describe as an example the neutral pressure gauges in the Wendelstein 7-X stellarator. Two types are used: Hot cathode ionization gauges (or ASDEX pressure gauges) and Penning gauges. We show some results from the first experimental campaign. Main problems were runtime effects and the failure of some ASDEX pressure gauges. To improve the reliability we integrated a new LaB 6 electron emitter into the ASDEX pressure gauges. A special Penning gauge without permanent magnets was developed in order to operate Penning gauges in the vacuum vessel, too. These new pressure gauges will be used in the upcoming campaign of Wendelstein 7-X.

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“…20 The pressure gauges were placed at front-ends of vacuum plug-ins at the midplane outboard side in all five stellarator modules for investigations of the toroidal symmetry. In Fig.…”

Section: Diagnostics For Plasma Edge and In-vessel Componentsmentioning

confidence: 99%

Overview of diagnostic performance and results for the first operation phase in Wendelstein 7-X (invited)

Krychowiak

Adnan

Alonso

et al. 2016

Review of Scientific Instruments

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Wendelstein 7-X, a superconducting optimized stellarator built in Greifswald/Germany, started its first plasmas with the last closed flux surface (LCFS) defined by 5 uncooled graphite limiters in December 2015. At the end of the 10 weeks long experimental campaign (OP1.1) more than 20 independent diagnostic systems were in operation, allowing detailed studies of many interesting plasma phenomena. For example, fast neutral gas manometers supported by video cameras (including one fast-frame camera with frame rates of tens of kHz) as well as visible cameras with different interference filters, with field of views covering all ten half-modules of the stellarator, discovered a MARFE-like radiation zone on the inboard side of machine module 4. This structure is presumably triggered by an inadvertent plasma-wall interaction in module 4 resulting in a high impurity influx that terminates some discharges by radiation cooling. The main plasma parameters achieved in OP1.1 exceeded predicted values in discharges of a length reaching 6 s. Although OP1.1 is characterized by short pulses, many of the diagnostics are already designed for quasi-steady state operation of 30 min discharges heated at 10 MW of ECRH. An overview of diagnostic performance for OP1.1 is given, including some highlights from the physics campaigns.

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Development of miniaturized, spectroscopically assisted Penning gauges for fractional helium and hydrogen neutral pressure measurements

Cited by 6 publications

References 11 publications

Upgrades of edge, divertor and scrape-off layer diagnostics of W7‐X for OP1.2

Upgrades of edge, divertor and scrape-off layer diagnostics of W7‐X for OP1.2

Advanced neutral gas diagnostics for magnetic confinement devices

Overview of diagnostic performance and results for the first operation phase in Wendelstein 7-X (invited)

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