Influence of impurity and particle control on Tandem Mirror Experiment Upgrade plasma operation

Journal Article · Thu May 01 00:00:00 EDT 1986 · J. Vac. Sci. Technol., A; (United States)

DOI:https://doi.org/10.1116/1.573454· OSTI ID:5520621

Allen, S L; Yu, T L; Foote, J H; Pickles, W L

A variety of techniques are used in Tandem Mirror Experiment-Upgrade (TMX-U)= to control impurities and reflux: repeated plasma pulses, glow discharge cleaning (GDC), and gettering. We performed a series of experiments under three different plasma-wall conditions: no wall conditioning after a machine maintenance cycle, glow-discharge-cleaned wall, and a gettered wall. We used several plasma diagnostics to determine the effect of these procedures on TMX-U plasma parameters. Spectroscopic measurements show that GDC reduces impurities and increases the electron temperature, enabling full-duration beam-sustained plasma operation without a large number of repeated plasma pulses. Gettering further reduces the impurities and the neutral pressure; this improved condition persists for several shots after gettering is stopped. Measurements from residual gas analyzers and an end-loss ion spectrometer show that hydrogen is present in the plasma during the initial deuterium operation after pumpdown; the hydrogen level decreases after plasma operation with gettering, indicating reduced wall recycling.

• Research Organization: Lawrence Livermore National Laboratory, Livermore, California 94550
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5520621
• Journal Information: J. Vac. Sci. Technol., A; (United States), Vol. 4:3
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
TMX DEVICES
IMPURITIES
OPERATION
DEUTERIUM
ELECTRON TEMPERATURE
GAS ANALYSIS
GETTERING
GLOW DISCHARGES
HYDROGEN
PLASMA DIAGNOSTICS
REPROCESSING
SURFACE CLEANING
WALLS
CLEANING
ELECTRIC DISCHARGES
ELEMENTS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
MAGNETIC MIRRORS
NONMETALS
NUCLEI
ODD-ODD NUCLEI
OPEN PLASMA DEVICES
SEPARATION PROCESSES
STABLE ISOTOPES
SURFACE FINISHING
TANDEM MIRRORS
THERMONUCLEAR DEVICES
700209* - Fusion Power Plant Technology- Component Development & Materials Testing