Electron pressure balance in the SOL through the transition to detachment
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- General Atomics, San Diego, CA (United States)
- Aalto Univ., Espoo (Finland)
- Univ. of California San Diego, La Jolla, CA (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Univ. of Toronto Institute for Aerospace Studies, Toronto (Canada)
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Upgrades to core and divertor Thomson scattering (DTS) diagnostics at DIII-D have provided measurements of electron pressure profiles in the lower divertor from attached- to fully-detached divertor plasma conditions. Detailed, multistep sequences of discharges with increasing line-averaged density were run at several levels of Pinj. Strike point sweeping allowed 2D divertor characterization using DTS optimized to measure Te down to 0.5 eV. The ionization front at the onset of detachment is found to move upwards in a controlled manner consistent with the indication that scrape-off layer parallel power flux is converted from conducted to convective heat transport. Measurements of ne, Te and pe in the divertor versus Lparallel demonstrate a rapid transition from Te ≥ 15 eV to ≤3 eV occurring both at the outer strike point and upstream of the X-point. Furthermore, these observations provide a strong benchmark for ongoing modeling of divertor detachment for existing and future tokamak devices.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- Grant/Contract Number:
- AC05-00OR22725; AC52-07NA27344; FC02-04ER54698; FG02-07ER54917; AC04-94AL85000
- OSTI ID:
- 1265737
- Alternate ID(s):
- OSTI ID: 1252232
- Journal Information:
- Journal of Nuclear Materials, Vol. 463, Issue C; ISSN 0022-3115
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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