Calibrated helium and carbon ion flow measurements in the DIII-D divertor plasma

S. L. Allen (Corresponding Author), C. M. Samuell, W. H. Meyer, A. E. Jaervinen, G. D. Porter, T. Rognlien

Research output: Contribution to journalArticleScientificpeer-review

1 Citation (Scopus)

Abstract

To explore the influence of drifts on ion flows in the DIII-D divertor and Scrape-Off-Layer (SOL), a calibrated Coherence Imaging System (CIS) views the lower divertor. A new tuneable calibration laser and precision wavemeter provide the rest wavelength for CIII 465 nm plasma emissions resulting in ≤ 1 km/s uncertainty in ion velocities that are in the range of 30 km/s in the divertor plasma. The 2-D line-integrated velocity images have been tomographically inverted to obtain maps of ion velocity. Both He + and C 2+ ion velocity maps were measured in both directions of the toroidal magnetic field B T , and C 2+ images were obtained in attached and detached L- and H-mode plasmas. The measured C 2+ velocities are in the range of 20–30 km/s and are compared with UEDGE modeling with full drifts. While He II as a main ion is expected to be entrained in the plasma flow, the C 2+ impurity flow involves the competition between the frictional and ion temperature gradient forces. Both the CIS data and UEDGE modeling agree that the C 2+ flow is towards the divertor plates, but flips with the direction of B T . In general, the experimental C 2+ emission and flow profiles have a wider spatial extent than the UEDGE modeling.

Original languageEnglish
Pages (from-to)137-142
Number of pages6
JournalNuclear Materials and Energy
Volume19
DOIs
Publication statusPublished - May 2019
MoE publication typeA1 Journal article-refereed

Keywords

  • Coherence imaging
  • DIII-D tokamak
  • Divertor and scrape off layer
  • Ion flow

Fingerprint

Dive into the research topics of 'Calibrated helium and carbon ion flow measurements in the DIII-D divertor plasma'. Together they form a unique fingerprint.

Cite this