ISSN:
1089-7666
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Energy and particle transport processes in Alcator C [Phys. Rev. Lett. 60, 298, (1988)] discharges heated by directly launched ion Bernstein waves (IBW) are investigated using the onetwo transport code [Nucl. Fusion 26, 329 (1986)]. The dependence of the observed ion heating rate (ΔTH/Prf) on plasma density is shown to result mainly from the inherent ion energy confinement that is characteristic of these discharges in the Ohmic phase and not on IBW propagation and absorption characteristics. The inferred value of the Ohmic ion thermal conduction exhibits an increasing anomaly with increasing plasma density. At a plasma density of n¯e (approximately-less-than)1×1020 m−3, the inferred ion thermal conduction is nearly equal to the Chang–Hinton neoclassical prediction. However, at a plasma density of n¯e (approximately-greater-than)2×1020 m−3, the inferred ion thermal conduction increases to about 5–8 times the Chang–Hinton neoclassical value. This increasing anomaly, which may result from the ion temperature gradient driven instability, can essentially account for the observed ion heating rate behavior during IBW heating. The effect of edge turbulence on IBW propagation is modeled using a Monte Carlo direct sampling simulation. The result is mainly a radial broadening of the calculated power deposition profile with increasing plasma density.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.858947
Permalink