Recent results from tokamak divertor plasma measurements

Journal Article · Sat Feb 01 04:00:00 EST 1997 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.1147897· OSTI ID:451081

Allen, S L ^[1]

---

1. Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)

New diagnostics have been developed to address key divertor physics questions, including: target plate heat flux reduction by radiation, basic edge transport issues, and plasma wall interactions (PWIs) such as erosion. A system of diagnostics measures the target plate heat flux (imaging ir thermography) and particle flux (probes, pressure and Penning gauges, and visible emission arrays). Recently, {ital T{sub e}}, {ital n{sub e}}, and {ital P{sub e}} (electron pressure) have been measured in two-dimensions (2D) with divertor Thomson Scattering. During radiative divertor operation {ital T{sub e}} is less than 2 eV, indicating that new atomic processes are important. Langmuir probes measure higher {ital T{sub e}} in some cases. In addition, the measured {ital P{sub e}} near the separatrix at the target plate is lower than the midplane pressure, implying radial momentum transport. Bolometer arrays, inverted with reconstruction algorithms, provide the two-dimensional core and divertor radiation profiles. Spectroscopic measurements identify the radiating species and provide information on impurity transport; both absolute chordal measurements and tomographic reconstructions of images are used. Either intrinsic carbon or an inert species (e.g., injected Ne) are usually observed, and absolute particle inventories are obtained. Computer codes are both benchmarked with the experimental data and provide important consistency checks. Several techniques are used to measure fundamental plasma transport and fluctuations, including probes and reflectometry. PWI issues are studied with {ital in situ} coupons and insertable samples (DiMES). Representative divertor results from DIII-D with references to results on other tokamaks will be presented. {copyright} {ital 1997 American Institute of Physics.}

• Research Organization: General Atomics
• DOE Contract Number: AC03-89ER51114; W-7405-ENG-48
• OSTI ID: 451081
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 2 Vol. 68; ISSN RSINAK; ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CHARGED-PARTICLE TRANSPORT
DIVERTORS
ELECTRON TEMPERATURE
LANGMUIR PROBE
PLASMA DENSITY
PLASMA DIAGNOSTICS
PLASMA IMPURITIES
PLASMA PRESSURE
THERMONUCLEAR REACTOR WALLS
TOKAMAK DEVICES
WALL LOADING