Determination of 2D poloidal maps of the intrinsic W density for transport studies in JET-ILW

The experimental method developed at ASDEX Upgrade for the determination of the intrinsic tungsten (W) density profile coupling data from the soft X-ray (SXR) diagnostic and vacuum-ultra-violet (VUV) spectroscopy has been upgraded for application to JET plasmas. The strong poloidal asymmetries in th...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Review of scientific instruments 2018-11, Vol.89 (11), p.113501-113501
Hauptverfasser: Sertoli, Marco, Flanagan, Joanne, Maslov, Mikhail, Maggi, Costanza, Coffey, Ivor, Giroud, Carine, Menmuir, Sheena, Carvalho, Pedro, Shaw, Anthony, Delabie, Ephrem
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:The experimental method developed at ASDEX Upgrade for the determination of the intrinsic tungsten (W) density profile coupling data from the soft X-ray (SXR) diagnostic and vacuum-ultra-violet (VUV) spectroscopy has been upgraded for application to JET plasmas. The strong poloidal asymmetries in the SXR emission are modeled assuming a ln(ϵ(ρ,R)/ϵ(ρ,R0))=λ(ρ)(R2−R02) distribution, where ρ is the flux coordinate, R is the major radius, and λ is the fit parameter. The W density is calculated from the resulting 2D SXR emissivity maps accounting for contributions from a low-Z impurity (typically beryllium) and main ion with the assumption that their contributions are poloidally symmetric. Comparing the result with the independent W concentration measurement of VUV spectroscopy, a recalibration factor for the SXR emissivity is calculated making the method robust against the decrease in the sensitivity of the SXR diodes which has been observed across multiple campaigns. The final 2D W density map is checked for consistency versus the time-evolution of the W concentration measurement from VUV spectroscopy, toroidal rotation measurements from charge exchange recombination spectroscopy, and tomographic reconstructions of bolometry data. The method has been found to be robust for W concentrations above a few 10−5 and in cases where the contributions from other medium-Z impurities such as Ni are negligible.
ISSN:0034-6748
1089-7623
1089-7623
DOI:10.1063/1.5046562