Plasma Physics and Controlled Fusion · 1984 · 64 citations · 6 references
Natural SciencesNuclear EngineeringPhysicsElectromagneticsPlasma PhysicsRadiation PhysicsCurrent DriveFusion PlasmasHigh-temperature PlasmasMagnetized PlasmaPlasma ConfinementPlasma WavesBremsstrahlung EmissionCritical Current DensityCurrent Drive In TokamaksLower Hybrid Current DriveQuasilinear TheoryRadio Frequency Current DriveTokamak PhysicsTokamak Plasmas
Current drive is applied to plasma and current start‑up and transformer recharging. The paper reviews experimental results on lower hybrid current drive in tokamak plasmas and summarizes evidence for a collisional scaling law for current‑drive efficiency. The review covers experimental results on lower hybrid current drive in tokamak plasmas and notes that microwave emission below the plasma frequency may reveal the underlying mechanism. Experiments achieved 3.5‑s pulses and >400 kA currents at densities where the wave frequency exceeds twice the lower hybrid frequency; current drive ceases above a critical density that rises with frequency, with f = 4.6 GHz reaching nc≈10¹⁴ cm⁻³ and no upper limit yet set, while bremsstrahlung X‑ray data agree qualitatively with quasilinear theory.
This paper reviews the experimental results on lower hybrid current drive in tokamak plasmas. Pulse lengths of 3.5 seconds and currents above 400 kA have been generated at plasma densities such that the wave frequency is greater than about twice the lower hybrid frequency. Current drive ceases above a critical density, nc. However, nc increases with wave frequency. So that for f = 4.6 GHz current drive has been seen at ec ≈1014 cm-3 and a density limit has yet to be established. Evidence for a collisional scaling law for current-drive efficiency is summarized. Detailed measurements of bremsstrahlung X-rays show a distribution which is qualitatively similar to that predicted by quasilinear theory. Microwave emission at frequencies less than the plasma frequency may shed light on the current-drive mechanisn. Applications of current drive including plasma and current start-up and transformer recharging are discussed.
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Confining a Tokamak Plasma with rf-Driven Currents
N. J. Fisch · Physical Review Letters · 1978 · 604 citations
Lower-Hybrid Current Drive in the PLT Tokamak
S. Bernabei, C. Daughney, P. C. Efthimion et al. · Physical Review Letters · 1982 · 249 citations
Experimental Observation of the rf-Driven Current by the Lower-Hybrid Wave in a Tokamak
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Toroidal Plasma Current Startup and Sustainment by rf in the WT-2 Tokamak
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