H. Leggate

ICRH of JET and LHD Majority Ions at Their Fundamental Cyclotron Frequency

Results of the experimental studies of ICRH at the fundamental cyclotron frequency of the majority deuterons in JET plasmas with near‐tangential deuteron neutral beam injection (NBI) are presented. 1D, 2D and 3D ICRH modeling indicated that several ITER relevant mechanisms of heating may occur simultaneously in this heating scheme: fundamental ion cyclotron resonance heating of majority and beam D ions, impurity ion heating and electron heating due to Landau damping and TTMP. These mechanisms were studied in JET experiments with a ∼90% D, 5% H plasma including traces of Be and Ar. Up to 2MW of ICRH power was applied at 25 MHz to NBI heated plasmas. In most of the discharges the toroidal magnetic field strength was 3.3T, but in one it was equal to 3.6T. The E+ component of the electric field governs the ion cyclotron heating of not too fast particles. The Doppler shifted RF absorption of the beam deuterons away from the cold resonance at which E+ is small was exploited to enhance the RF power absorption ef...

Influence of plasma background on 3D scrape-off layer filaments

This paper presents the effect of self-consistent plasma backgrounds including plasma-neutral interactions, on the dynamics of filament propagation. The principle focus is on the influence of the neutrals on the filament through both direct interactions and through their influence on the plasma background. Both direct and indirect interactions influence the motion of filaments. A monotonic increase of filament peak velocity with upstream electron temperature is observed, while a decrease with increasing electron density is observed. If ordered by the target temperature, the density dependence disappears and the filament velocity is only a function of the target temperature. Smaller filaments keep a density dependence, as a result of the density dependence of the plasma viscosity. The critical size

Influence of plasma background including neutrals on scrape-off layer filaments using 3D simulations

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Verification of high performance two-dimensional particle-in-cell simulations of low-temperature plasmas

, where filaments are fastest, is shifted to larger sizes for higher densities, due to the plasma viscosity. If the density dependence of the plasma viscosity is removed,

Radio-frequency sheaths in grazing angle magnetic fields

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Improved Confinement in JET hybrid discharges

has no temperature dependence, but rather a density dependence.