No abstract available

No abstract available

[en] Up to 820 kW of rf power is delivered to the only 460 cm² area of antennae with the radiation resistance about 1 Ω. The radiation resistance agrees well with the strong damping model. A plan for ridge wave guide coupling in JFT-2M is also shown. (author)

[en] Impurities during the ICRF heating experiment in JFT-2 are presented. One attempt to reduce impurities and to improve a heating efficiency is shown. (author)

[en] A safety design approach for the Japanese Demonstration Fast Breeder Reactor (DFBR) is discussed to establish the same level of safety as that of LWR. This argument has been made taking well account of the experience of the prototype FBR Monju, and contains major safety issues as follows; efforts of the reduction of sodium void reactivity worth, adoption of self actuated mechanism in the backup shutdown system, use of the direct reactor auxiliary cooling system as the decay heat removal system, and provision of the containment system. (author)

No abstract available

[en] Up to 600 KW of ICRF power is coupled to plasma with the small area antennae (460 cm²). Around Psub(net) = 500 kW, ion temperature increases from 0.4 to 0.8 keV, that of electron 0.6 to 0.9 keV, and increase of βsub(p) is 0.35 approx. 0.4. Clear dependence on the nsub(H)/nsub(D) is not observed. Deuterium high energy tail is observed, which indicates a direct absorption of rf power by deuterium. (author)

[en] Reduction of impurity line emissions associated with the ion cyclotron range of frequency (ICRF) heating is achieved by the phase control of a loop antenna array. Reduction in metal impurity emissions and radiation loss is closely correlated with the amount of power radiated from the antennae with parallel wave number near ksub(parallel)=0. The maximum density attainable without disruption is increased over that in the Ohmic heating phase, by reduction of radiation loss. (author)

[en] High-field-side excitation is investigated in detail in the JFT-2 ICRF heating experiment. For nsub(H)/nsub(D)<=10%, the RF-power preferentially couples with the ions in the plasma core. Specifically, D-majority heating is dominant in the very dilute minority region (nsub(H)/nsub(D)=2-4%). The non-Maxwellian high-energy tail of D, which indicates direct power absorption, is confirmed by the mass-discriminating charge exchange spectra. The power deposition profile is reasonably centrally peaked, which is confirmed by the Bsub(T) scan and also by an analysis of the temperature profiles. With Psub(net) approx.= 500 kW, the central ion temperature increase from 0.4 keV to 0.7 keV, and the central electron temperature from 0.5 keV to 0.75 keV at n-barsub(e) approx.= 5x10₁₃ cm^-₃ and nsub(H)/nsub(D)=2-4%. For the mode conversion regime (nsub(H)/nsub(D) >or approx. 30%), the RF-power couples dominantly with electrons. Bsub(T) and nsub(H)/nsub(D) scans indicate that maximum δTsub(e)(0) is obtained when the two-ion hybrid resonance layer is shifted by about 7 cm off the vessel axis. This observation can be explained by the propagation characteristics of an ion Bernstein wave. Some ion heating mechanism exists even in this regime. It is found that the ion heating is sensitive to the amount of impurity ions such as Fe and Ti, suggesting that the ion heating may be due to harmonic cyclotron damping by impurities. The origin of metal impurities during heating is investigated in the mode conversion regime. A strong correlation is confirmed between influx and fast ions localized in the scrape-off layer. (author)

[en] The H-mode can be achieved in NBI and/or ICRF heated open divertor discharges, and an H-transition with improved energy confinement is also observed in limiter discharges with both heating methods. The gross energy confinement time τ_EG in the H-mode recovers that of the Ohmic plasma. A large improvement in gross energy confinement is also observed after injection of a single pellet into an NBI heated plasma, where during the first 40 ms after pellet injection 70% of the NBI power is stored in the plasma. τ_EG reaches 70 ms, which is about twice the Ohmic value. In an additionally heated plasma, the incremental stored energy behaves as if it had its own energy confinement time τ_ad, which is independent of the heating power. In some cases of H-modes, τ_ad is equal to the doubled L-mode value. (author)