Development of slow and fast wave coupling and heating from the C-Stellarator to NSTX

Hosea, J.

doi:10.1051/epjconf/201715702003

Cited by 2 publications

(1 citation statement)

References 25 publications

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“…On account of the fact that the power density is proportional to the density via the square of the plasma frequency and since k ⊥ ρ L is small for the (fast magneto-sonic) wave commonly relied on for achieving radio frequency heating, one historically (see e.g. [10]) first tested majority heating at ω = Ω. It was quickly realised that the presence of the plasma impacts strongly on the wave polarisation.…”

Section: Basics Of Rf Wave Induced Plasma Heatingmentioning

confidence: 99%

Ion cyclotron resonance heating scenarios for DEMO

Eester¹,

Lerche²,

Ragona³

et al. 2019

Nucl. Fusion

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The present paper offers an overview of the potential of ion cyclotron resonance heating (ICRH) or radio frequency (RF) heating for the DEMO machine. It is found that various suitable heating schemes are available. Similar to ITER and in view of the limited bandwidth of about 10M Hz that can be achieved to ensure optimal functioning of the launcher, it is proposed to make core second harmonic tritium heating the key ion heating scheme, assisted by fundamental cyclotron heating 3 He in the early phase of the discharge; for the present design of DEMO-with a static magnetic field strength of B o = 5.855T-that places the T and 3 He layers in the core for f = 60M Hz and suggests to center the bandwidth around that main operating frequency. In line with earlier studies for hot, dense plasmas in large-size magnetic confinement machines it is shown that good single pass absorption is achieved but that the size as well as operating density and temperature of the machine cause the electrons to absorb a non-negligible fraction of the power away from the core when core ion heating is aimed at. Current drive and alternative heating options are briefly discussed and a dedicated computation is done for the traveling wave antenna, proposed for DEMO in view of its compatibility with substantial antenna-plasma distances. The various tasks that ICRH can fulfill are briefly listed. Finally, the impact of transport and the sensitivity of the obtained results to changes in the machine parameters is commented on.

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Section: Basics Of Rf Wave Induced Plasma Heatingmentioning

confidence: 99%

Ion cyclotron resonance heating scenarios for DEMO

Eester¹,

Lerche²,

Ragona³

et al. 2019

Nucl. Fusion

View full text Add to dashboard Cite

show abstract

Effect of wall boundary on the scrape-off layer losses of high harmonic fast wave in NSTX and NSTX-U

et al. 2019

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We perform numerical simulations of high harmonic fast waves (HHFWs) in the scrape-off-layer (SOL) of National Spherical Torus Experiment (NSTX)/NSTX-U using a recently developed 2D full wave code. We particularly show that a realistic NSTX SOL boundary can significantly affect HHFW propagation and power losses in the SOL. In NSTX SOL boundaries, HHFW is easily localized near the antenna and propagates less to the SOL, and thus, less power is lost to the SOL. We also show that the lower SOL power losses occur when the SOL volume is smaller and the distance between the last closed flux surface and the antenna is shorter. We investigate the effect of electron density in front of the antenna and the ambient magnetic field strengths on the SOL power losses as well. Showing consistency with the experiments, SOL losses are minimized when the SOL density is near the critical density where the fast wave cutoff is open, and the plasma is strongly magnetized.

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Development of slow and fast wave coupling and heating from the C-Stellarator to NSTX

Cited by 2 publications

References 25 publications

Ion cyclotron resonance heating scenarios for DEMO

Ion cyclotron resonance heating scenarios for DEMO

Effect of wall boundary on the scrape-off layer losses of high harmonic fast wave in NSTX and NSTX-U

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