Design, manufacture and testing of the glow discharge electrodes for Wendelstein 7-X

Spring, A.; Cardella, A.; Brucker, B.; Mendelevitch, B.; Niedermeyer, H.; Sellmeier, O.; Schweizer, Sabine; Streibl, B.

doi:10.1016/j.fusengdes.2011.02.018

Cited by 4 publications

(4 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The glow discharge system is equipped with 10 graphite anodes operated at maximum current of 1.5 A (within 3 kW) for each unit [7]. The optimization of GDC parameters was done in OP1.2a.…”

Section: Glow Discharge Cleaningmentioning

confidence: 99%

Wall conditioning at the Wendelstein 7-X stellarator operating with a graphite divertor

Goriaev

Wauters²,

Brakel

et al. 2020

Phys. Scr.

View full text Add to dashboard Cite

Wall conditioning plays an important role in achieving record plasma performance on superconducting stellarator Wendelstein 7-X (W7-X) by controlling plasma density and keeping low level of impurities. The development of the optimal wall conditioning strategy is of high importance for successful operation of W7-X with graphite divertor. The current strategy consists of initial wall conditioning applied prior to physics experimental program and wall conditioning techniques executed during plasma operation phase. The combination of baking and glow discharge cleaning (GDC) provides fast start of reliable plasma operation. Regular boronisation opens a new operational window of high plasma densities above 1*10 20 m -3 . Strong wall fueling remains however one of the main issues preventing plasma density control. A reliable solution is provided by application of He ECRH pulse trains which are optimised to maximise fuel removal.

show abstract

“…The glow discharge system is equipped with 10 graphite anodes operated at maximum current of 1.5 A (within 3 kW) for each unit [7]. The optimization of GDC parameters was done in OP1.2a.…”

Section: Glow Discharge Cleaningmentioning

confidence: 99%

Wall conditioning at the Wendelstein 7-X stellarator operating with a graphite divertor

Goriaev

Wauters²,

Brakel

et al. 2020

Phys. Scr.

View full text Add to dashboard Cite

show abstract

“…14 It comprises a prototype W7-X glow discharge anode, which is characterized by a reliable thermal and discharge stability. 15 The anode made of graphite has a spherical calotte shape with a diameter of 150 mm [Fig. 7(a)].…”

Section: B Systems Of Plasma Production 1 Glow Discharge Systemmentioning

confidence: 99%

“…The maximum temperature of the anode surface would stay below 390 ○ C at a maximum anode current of 3 A in the pressure range of 4 ×10 −3 mbar-1 ×10 −2 mbar. 15 The anode is connected to the power line via a single copper pin CF 40 vacuum feedthrough with a pin FIG. 6.…”

Section: B Systems Of Plasma Production 1 Glow Discharge Systemmentioning

confidence: 99%

The upgraded TOMAS device: A toroidal plasma facility for wall conditioning, plasma production, and plasma–surface interaction studies

Goriaev

Wauters²,

Möller

et al. 2021

Review of Scientific Instruments

View full text Add to dashboard Cite

The Toroidal Magnetized System device has been significantly upgraded to enable development of various wall conditioning techniques, including methods based on ion and electron cyclotron (IC/EC) range of frequency plasmas, and to complement plasma-wall interaction research in tokamaks and stellarators. The toroidal magnetic field generated by 16 coils can reach its maximum of 125 mT on the toroidal axis. The EC system is operated at 2.45 GHz with up to 6 kW forward power. The IC system can couple up to 6 kW in the frequency range of 10 MHz-50 MHz. The direct current glow discharge system is based on a graphite anode with a maximum voltage of 1.5 kV and a current of 6 A. A load-lock system with a vertical manipulator allows exposure of material samples. A number of diagnostics have been installed: singleand triple-pin Langmuir probes for radial plasma profiles, a time-of-flight neutral particle analyzer capable of detecting neutrals in the energy range of 10 eV-1000 eV, and a quadrupole mass spectrometer and video systems for plasma imaging. The majority of systems and diagnostics are controlled by the Siemens SIMATIC S7 system, which also provides safety interlocks.

show abstract

“…One W7-X prototype electrode [8] was installed over three experimental campaigns from 2008 to 2011 in the AUG vacuum vessel. It was operated in combination with the originally installed rod-type electrodes replacing one of the four.…”

Section: Technical Setup Aug Gd System 31 Gd Electrodes and Startingmentioning

confidence: 99%

Optimization of the ASDEX Upgrade glow discharge

Härtl

Drenik

Kircher

et al. 2017

Fusion Engineering and Design

View full text Add to dashboard Cite

The ASDEX Upgrade (AUG) system for glow discharge (GD) has been revised comprehensively. This was necessary due to technical as well as operational requirements. The available space with in the low field side of the vacuum vessel is strongly limited because it's the preferred place for diagnostics. The new development based on the design of the W7-X anode now has a smaller footprint, is long term reliable and easier maintainable. Additionally each of the anodes is equipped with a separate starting device. The use of this device now allows the fast ignition of GD at operational pressure without the need of a short-term pressure increase. With the change from carbon to tungsten plasma-facing components (PFCs) an enhanced Helium (He) content at plasma discharges was observed for unboronized walls and the implantation of He during GD could be identified as source. For this reason the use of He GD has to be strongly reduced. It turned out that pulsed GDs of about 10 seconds length followed by a pumping down phase are sufficient to clean the wall. This mode of operation requires a reliable breakdown of the GD at operating pressure. This paper gives an overview of the technical setup and first measurement results.

show abstract

Design, manufacture and testing of the glow discharge electrodes for Wendelstein 7-X

Cited by 4 publications

References 5 publications

Wall conditioning at the Wendelstein 7-X stellarator operating with a graphite divertor

Wall conditioning at the Wendelstein 7-X stellarator operating with a graphite divertor

The upgraded TOMAS device: A toroidal plasma facility for wall conditioning, plasma production, and plasma–surface interaction studies

Optimization of the ASDEX Upgrade glow discharge

Contact Info

Product

Resources

About