Key results of long pulse ICRH operation in Tore Supra

Colas, L.; Basiuk, V.; Beaumont, B.; Bécoulet, A.; Bosia, G.; Brémond, Sylvain; Chantant, M.; Clairet, F.; Ekedahl, A.; Faudot, E.; Geraud, A.; Goniche, M.; Heuraux, Stéphane; Hoang, G. T.; Lombard, Gilles; Millon, L.; Mitteau, R.; Mollard, Patrick; Vulliez, K.

doi:10.1088/0029-5515/46/7/s11

Cited by 43 publications

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As mentioned previously, this trend is also observed in low harmonic ICRF heating in conventional tokamaks, where the core heating efficiency with 180˚ phasing is always substantially higher than that obtained with 0˚ phasing [15]. A number of mechanisms have been proposed, including collisional losses [15], surface wave propagation associated with large poloidal wave numbers excited by sharp boundaries of the current strap in the poloidal direction [15], antenna reactive field losses [8] and rf sheath dissipation [16,17,18]. The power losses from most of these mechanisms are predicted to increase at higher edge densities.…”

Section: Fast Wave Core Heating Efficiencies In Nstxsupporting

confidence: 54%

Spectral effects on fast wave core heating and current drive

et al. 2009

View full text Add to dashboard Buy / Rent full text

Abstract. Recent results obtained with high harmonic fast wave (HHFW) heating and current drive (CD) on NSTX strongly support the hypothesis that the onset of perpendicular fast wave propagation right at or very near the launcher is a primary cause for a reduction in core heating efficiency at long wavelengths that is also observed in ICRF heating experiments in numerous tokamaks. A dramatic increase in core heating efficiency was first achieved in NSTX L-mode helium majority plasmas when the onset for perpendicular wave propagation was moved away from the antenna and nearby vessel structures. Efficient core heating in deuterium majority L mode and H mode discharges, in which the edge density is typically higher than in comparable helium majority plasmas, was then accomplished by reducing the edge density in front of the launcher with lithium conditioning and avoiding operational points prone to instabilities. These results indicate that careful tailoring of the edge density profiles in ITER should be considered to limit rf power losses to the antenna and plasma facing materials. Finally, in plasmas with reduced rf power losses in the edge regions, the first direct measurements of high harmonic fast wave current drive were obtained with the motional Stark effect (MSE) diagnostic. The location and radial dependence of HHFW CD measured by MSE are in reasonable agreement with predictions from both full wave and ray tracing simulations.

show abstract

Section: Fast Wave Core Heating Efficiencies In Nstxsupporting

confidence: 54%

Spectral effects on fast wave core heating and current drive

et al. 2009

View full text Add to dashboard Buy / Rent full text

show abstract

“…This parametric dependence is valuable for design and experimental studies. In particular, the RFinduced heat loads in the RF antenna vicinity were inferred experimentally to scale as E //ap 1 , 29,30 consistent with the first order theory. The particular simulation showed in Ref.…”

Section: -13supporting

confidence: 69%

“…6,16,29,[31][32][33] A. RF part of the model: Full-wave propagation in bounded 3-dimensional (3D) SOL plasma…”

Section: Outline Of Sswich Modelmentioning

confidence: 99%

“…From a practical point of view, this is also a critical regime since experimentally the deleterious plasma-wall interaction related to the sheaths gets exacerbated at high RF power. 18,[28][29][30] Sections III and IV detail the asymptotic resolution for several configurations of the excitation and of the target plasma. The way to refine iteratively the solution from its asymptotic value is also outlined.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Self consistent radio-frequency wave propagation and peripheral direct current plasma biasing: Simplified three dimensional non-linear treatment in the “wide sheath” asymptotic regime

Colas¹,

Jacquot²,

Heuraux³

et al. 2012

Physics of Plasmas

View full text Add to dashboard Buy / Rent full text

“…by restricting operation to high-k || phasing 7 or lower power levels. In longer-pulse experiments 15 and future burning plasma experiments, the requirements will be even more severe: even a small level of antenna-plasma interaction may result damaging localized heat deposition during the shot.…”

Section: Introductionmentioning

confidence: 99%

A radio-frequency sheath boundary condition and its effect on slow wave propagation

D'Ippolito¹,

Myra²

2006

Physics of Plasmas

View full text Add to dashboard Buy / Rent full text

Predictive modeling of radiofrequency wave propagation in high-power fusion experiments requires accounting for nonlinear losses of wave energy in the plasma edge and at the wall. An important mechanism of "anomalous" power losses is the acceleration of ions into the walls by rf sheath potentials. Previous work computed the "sheath power dissipation" non-self-consistently by post-processing fields obtained as the solution of models which did not retain sheaths. Here, a method is proposed for a self-consistent quantitative calculation of sheath losses by incorporating a sheath boundary condition (SBC) in antenna coupling and wave propagation codes. It obtains the self-consistent sheath potentials and spatial distribution of the time-averaged power loss in the solution for the linear rf fields. It can be applied for ion cyclotron and (in some cases) lower hybrid waves. The use of the SBC is illustrated by applying it to the problem of an electron plasma wave propagating in a waveguide. This model problem is relevant to understanding the low heating efficiency in direct ion-Bernstein wave launch.Implications for calculating sheath voltages driven by fast-wave antennas are also discussed.

show abstract

Key results of long pulse ICRH operation in Tore Supra

Cited by 43 publications

References 35 publications

Spectral effects on fast wave core heating and current drive

Spectral effects on fast wave core heating and current drive

Self consistent radio-frequency wave propagation and peripheral direct current plasma biasing: Simplified three dimensional non-linear treatment in the “wide sheath” asymptotic regime

A radio-frequency sheath boundary condition and its effect on slow wave propagation

Contact Info

Product

Resources

About