Physics of Plasmas · 2017 · 38 citations · 10 references
EngineeringNuclear EngineeringPhysicsFusion EngineeringNuclear Fuel CyclePlasma PhysicsFusion PlasmasHigh-temperature PlasmasMagnetic Confinement FusionNeutral Beam InjectionPlasma ConfinementPlasma-wall InteractionsAuxiliary HeatingElectron Density ProfilesPlasma Boundary ConditionsPlasma Boundary LayersPuffing PhenomenaScrape-off Layer PhysicsTemperature ProfilesTokamak Physics
High edge electron temperatures (200 eV or greater) have been measured at the wall-limited plasma boundary in the Lithium Tokamak Experiment (LTX). Flat electron temperature profiles are a long-predicted consequence of low recycling boundary conditions. Plasma density in the outer scrape-off layer is very low, 2–3 × 1017 m−3, consistent with a low recycling metallic lithium boundary. Despite the high edge temperature, the core impurity content is low. Zeff is estimated to be ∼1.2, with a very modest contribution (<0.1) from lithium. Experiments are transient. Gas puffing is used to increase the plasma density. After gas injection stops, the discharge density is allowed to drop, and the edge is pumped by the low recycling lithium wall. An upgrade to LTX–LTX-β, which includes a 35A, 20 kV neutral beam injector (on loan to LTX from Tri-Alpha Energy) to provide core fueling to maintain constant density, as well as auxiliary heating, is underway. LTX-β is briefly described.
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Observations concerning the injection of a lithium aerosol into the edge of TFTR discharges
D. K. Mansfield, D. Johnson, B. Grek et al. · Nuclear Fusion · 2001 · 107 citations