Limiter H-mode and other improved confinement regimes with ICRF and NBI heating in JIPP T-IIU

Watari, T.; Kumazawa, R.; Toi, K.; Masai, K.; Hamada, Y.; Andõ, Akira; Oka, Y.; Kaneko, O.; Kawahata, K.; Adati, K.; Akiyama, R.; Ando, R.; Aoki, Takashi; Fujita, J.; Hidekuma, S.; Hirokura, S.; Ida, K.; Ikegami, H.; Kadota, K.; Kako, E.; Karita, A.; Kawasumi, Y.; Kitagawa, S.; Kojima, M.; Kawamoto, T.; Kuroda, T.; Mohri, A.; Morita, S.; Narihara, K.; Ogawa, Yuichi; Ohkubo, Κ.; Okajima, S.; Ozaki, T.; Sagara, A.; Sakamoto, M.; Sasao, M.; Sato, K.; Sato, Toru; Seki, T.; Shimbo, F.; Takahashi, H.; Tanahashi, S.; Taniguchi, Y.; Tsuzuki, T.; Yamada, H.

doi:10.1088/0029-5515/30/7/002

Cited by 12 publications

(4 citation statements)

References 25 publications

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“…The total power for NBI+ICRF + 130 MHz heating is less than 1.5 MW, so that the ratio P|3OMH Z /(PNBI + PICRF) is larger than unity. In previous experiments with high power ICRF heating and NBI, reasonable heating efficiencies were obtained [28]. We stress here that the 3rd harmonic ion cyclotron heating has an efficiency comparable to that of established heating methods.…”

Section: Ion Heatingsupporting

confidence: 70%

“…1, eight antennas are installed on the high field side of the vacuum chamber, four of which form a 130 MHz antenna array aligned in the toroidal direction. The same antennas had been used in 40 MHz ion cyclotron range of frequency (ICRF) heating experiments [28,29]. Because of the shorter wavelength at 130 MHz, the antennas were shortened, so that their poloidal length was less than a quarter wavelength and the wave was radiated from the high field side around the equatorial plane.…”

Section: Experimental Set-upmentioning

confidence: 99%

“…The other antennas were used as 40 MHz ICRF heating antennas, as before [28,29]. The plasma was heated in the two-ion hybrid heating regime with a maximum power of 500 kW.…”

Section: Experimental Set-upmentioning

confidence: 99%

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Application of the intermediate frequency range fast wave to the JIPP TII-U plasma

et al. 1991

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A series of experiments has been conducted on the JIPP TII-U tokamak since 1989, using the newly constructed 130 MHz radiofrequency system. It has been predicted theoretically that the fast wave in this frequency range interacts weakly with particles. Two mechanisms of wave absorption have been identified in the experiment: electron Landau damping/transit time damping and 3rd harmonic ion cyclotron heating. The former mechanism is intimately connected with fast wave current drive and the latter can provide a new regime of plasma heating or a possible method of controlling the transport of alpha particles. It is found that the efficiency of the 3rd harmonic ion cyclotron heating is improved by using it in combination with neutral beam injection and ion cyclotron range of frequency heating. The heating efficiency obtained is as high as that of conventional heating. The experimental results are also analysed on the basis of a global wave theory which takes into account wave-particle interactions. These mechanisms of interaction are competing with each other; this will also be the case under more realistic reactor conditions.

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Section: Ion Heatingsupporting

confidence: 70%

Section: Experimental Set-upmentioning

confidence: 99%

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Application of the intermediate frequency range fast wave to the JIPP TII-U plasma

et al. 1991

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“…The most famous of these is the H-Mode which was first discovered on ASDEX [10]. Similarly other modes such as the Improved Ohmic Confinement ( IOC) [11,12], Pellet Enhanced Performance (PEP) [13,14] 19,20]. The study of these improved confinement regimes offers an opportunity for a better understanding of the underlying causes of anomalous transport.…”

Section: Previous Resultsmentioning

confidence: 99%

Measurement of particle transport coefficients on Alcator C-Mod

Luke¹

1994

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The study of particle transport is increasingly important for fusion research. During the 1993 and 1994 campaigns of Alcator C-Mod, one observed phenomenon was the divertor detachment. This phenomenon was characterized by reduced particle and energy flows to the divertor plates and is of interest as a solution to the heat loading problem of the first wall. A sharp rise in the central electron density was observed after detachment. The goal of this thesis was to study the behavior of the plasma transport during the divertor detachment in order to explain this density rise.The measurement of particle transport coefficients requires sophisticated diagnostic tools. A two color interferometer system was developed and installed on Alcator C-Mod to measure the electron density with high spatial (~ 2 cm ) and high temporal (5 1.0 ms) resolution. The system consists of 10 CO 2 (10.6 pm) and 4 HeNe ( .6328 4m) chords that are used to measure the line integrated density to within 0.08 CO 2 degrees or 2.3x 1016 m-2 theoretically.Using the two color interferometer, a series of gas puffing experiments were conducted. The density was varied above and below the threshold density for detachment at a constant magnetic field and plasma current. Using a gas modulation technique, the particle diffusion, D, and the convective velocity, V, were determined. Profiles were inverted using a SVD inversion and the transport coefficients were extracted with a time regression analysis and a transport simulation analysis. Results from each analysis were in good agreement.Measured profiles of the coefficients incriased with the radius and the values were consistent with measurements from other experiments. The values exceeded neoclassical predictions by a factor of 10. The profiles also exhibited an inverse dependence with plasma density. The scaling of both attached and detached plasmas agreed well with this inverse scaling. This result and the lack of change in the energy and impurity transport indicate that there was no change in the underlying transport processes after detachment. On the contrary, measurements of the Ha radiation and argon transport were consistent with a change in the electron source at the edge. Thus, the rise in central density was due to an increase in the overall electron source or a improvement in fueling efficiency and not due to an improvement in the core particle transport.

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Feedback Control Matching System for Temporal Change of Plasma Loading Resistance in High Power/Steady State Icrf Heating on the Large Helical Device

Kumazawa

Watari

Mutoh

et al. 1993

Fusion Technology 1992

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Limiter H-mode and other improved confinement regimes with ICRF and NBI heating in JIPP T-IIU

Cited by 12 publications

References 25 publications

Application of the intermediate frequency range fast wave to the JIPP TII-U plasma

Application of the intermediate frequency range fast wave to the JIPP TII-U plasma

Measurement of particle transport coefficients on Alcator C-Mod

Feedback Control Matching System for Temporal Change of Plasma Loading Resistance in High Power/Steady State Icrf Heating on the Large Helical Device

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