Feasibility of line-ratio spectroscopy on helium and neon as edge diagnostic tool for Wendelstein 7-X

Barbui, T.; Krychowiak, M.; König, R.; Schmitz, O.; Burgos, J. M. Muñoz; Schweer, B.; Terra, A.; Team, W X

doi:10.1063/1.4962989

Cited by 26 publications

(42 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An identical set-up, connected to the one in the lower divertor by an island chain, is installed in the upper divertor. Here, we will focus on the upper divertor, following the experimental work by [6]. Using both endoscope cameras, it is foreseen to reconstruct the spatial emission distributions of the five beams by tomographic methods.…”

Section: Application To W7-xmentioning

confidence: 99%

See 1 more Smart Citation

Synthetic helium beam diagnostic and underlying atomic data

Zholobenko

Rack²,

Reiter³

et al. 2018

Nucl. Fusion

View full text Add to dashboard Cite

We report on synthetic helium beam emission spectroscopy (BES) in fusion edge plasmas, as enabled by the 3D kinetic (neutral particle) transport code EIRENE. We also review and upgrade the underlying atomic helium data base, resorting to the most recent version of the Goto-Fujimoto collisional-radiative code and a recommended and publicly exposed reference cross section data set from an internationally coordinated (IAEA) evaluation activity. On the example of the Wendelstein 7-X (W7-X) stellarator, we use both the upgraded transport code and data base to simulate the penetration of and radiation from thermal helium used for BES in the island divertor region. This allows to evaluate the applicability of the diagnostic in different plasma backgrounds, simulated with the 3D edge plasma Monte Carlo code EMC3-EIRENE, and with different levels of refinement of underlying atomic data. The sensitivity of the diagnostic to the atomic data set-which is crucial for a quantitative determination of electron density and temperature profiles − is investigated and discussed, as well as the effects of p-He beam widening and correlated line-of-sight integration.

show abstract

Section: Application To W7-xmentioning

confidence: 99%

“…Thermal spread in beam source, meta-stable states [13] and p-He elastic scattering [29] are included, no recombination. Beam parameters are taken from [6,34]. Particle flux isṄ = 1.5 × 10 19 s −1 per beam.…”

Section: Application To W7-xmentioning

confidence: 99%

Synthetic helium beam diagnostic and underlying atomic data

Zholobenko

Rack²,

Reiter³

et al. 2018

Nucl. Fusion

View full text Add to dashboard Cite

show abstract

“…Another piezo system with a cascade of five inlet tubes is implemented in the stellerator W7-X in Greifswald 20 used as thermal helium beam 21 and fuelling valve as well as for impurity transport studies 22 .…”

Section: Gas Cloud Shapementioning

confidence: 99%

Fast piezoelectric valve offering controlled gas injection in magnetically confined fusion plasmas for diagnostic and fuelling purposes

Griener

Schmitz

Bald

et al. 2017

Review of Scientific Instruments

Self Cite

View full text Add to dashboard Cite

In magnetically confined fusion plasmas controlled gas injection is crucial for plasma fuelling as well as for various diagnostic applications such as active spectroscopy. We present a new, versatile system for the injection of collimated thermal gas beams into a vacuum chamber. This system consists of a gas pressure chamber, sealed by a custom made piezo valve towards a small capillary for gas injection. The setup can directly be placed inside of the vacuum chamber of fusion devices as it is small and immune against high magnetic fields. This enables gas injection close to the plasma periphery with high duty cycles and fast switch on/off times ≲ 0.5 ms. In this work, we present the design details of this new injection system and a systematic characterization of the beam properties as well as the gas flowrates which can be accomplished. The thin and relatively short capillary yields a small divergence of the injected beam with a half opening angle of 20°. The gas box is designed for pre-fill pressures of 10 mbar up to 100 bars and makes a flowrate accessible from 10 part/s up to 10 part/s. It hence is a versatile system for both diagnostic as well as fuelling applications. The implementation of this system in ASDEX Upgrade will be described and its application for line ratio spectroscopy on helium will be demonstrated on a selected example.

show abstract

“…10). The versatile gas injection system has been used for injection of helium for measurement of local edge n e and T e profiles 28 and effective particle confinement time τ p * He , 22 neon for development of a collisional radiative model to extend the parameter range and accuracy of the diagnostic helium beam, 28,29 argon for impurity transport studies as well as nitrogen for radiative edge cooling. Perpendicular observation of the gas emission at the upper plasma edge was done along 8 los, using quartz fibers and an imaging spectrometer with a CCD camera.…”

Section: Diagnostics For Plasma Edge and In-vessel Componentsmentioning

confidence: 99%

“…Perpendicular observation of the gas emission at the upper plasma edge was done along 8 los, using quartz fibers and an imaging spectrometer with a CCD camera. 28 A multipurpose manipulator with a fast reciprocating probe has been assembled at the outboard side near to the equatorial plane. Two probe heads were available: a combined probe measuring the edge plasma profiles or fluctuations (at fixed probe position) as well as a sample station for plasma exposure studies of different materials.…”

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

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Feasibility of line-ratio spectroscopy on helium and neon as edge diagnostic tool for Wendelstein 7-X

Cited by 26 publications

References 8 publications

Synthetic helium beam diagnostic and underlying atomic data

Synthetic helium beam diagnostic and underlying atomic data

Fast piezoelectric valve offering controlled gas injection in magnetically confined fusion plasmas for diagnostic and fuelling purposes

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

Contact Info

Product

Resources

About