RF heated wall conditioning discharges in JT-60U

Itami, K.; Asakura, N.; Tamai, Hiroshi; Moriyama, S.; Kaminaga, A.

doi:10.1016/j.jnucmat.2009.01.254

Cited by 20 publications

(20 citation statements)

References 14 publications

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“…Radial extension has been successfully demonstrated on JT60-U [5] and TORE SUPRA at the fundamental ECR and in KSTAR [35] for the both cases of fundamental and second harmonic absorption. The increase of wall coverage could be clearly correlated to the cleaning efficiency on TORE SUPRA.…”

Section: Principle Of Ecwc and Scenarios In Itermentioning

confidence: 92%

“…Many experiments were however performed using microwave frequencies close to 2.45 GHz at B T 6 0.1 T [33]. The use of frequencies above 110 GHz has been less and only recently investigated on TEXTOR, JT-60U, KSTAR and TORE SUPRA [5,34,35]. ECWC is foreseen as the sole conditioning method in the presence of the toroidal field in JT-60SA.…”

Section: Principle Of Ecwc and Scenarios In Itermentioning

confidence: 99%

“…In ITER however, the magnetic field, generated by superconducting coils, will be continuously maintained. Conventional Direct Current (DC) glow discharges being unstable in the presence of such an intense magnetic field, methods compatible with the permanent toroidal magnetic field of ITER, such as Ion (ICWC) [3,4] or Electron Cyclotron Wall Conditioning (ECWC) [5], are foreseen in ITER for fuel and impurity removal between plasma pulses.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Wall conditioning for ITER: Current experimental and modeling activities

Douai

Kogut

Wauters³

et al. 2015

Journal of Nuclear Materials

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Section: Principle Of Ecwc and Scenarios In Itermentioning

confidence: 92%

Section: Principle Of Ecwc and Scenarios In Itermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Wall conditioning for ITER: Current experimental and modeling activities

Douai

Kogut

Wauters³

et al. 2015

Journal of Nuclear Materials

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“…In JT-60SA, ECH wall-cleaning is planned. In the previous JT-60, an effectiveness of the ECH wall-cleaning using fundamental harmonic waves was demonstrated by K. Itami et al [17]. However, the effectiveness of the second harmonic waves for ECH wall-cleaning is not clear, so far.…”

Section: Oscillations At 82 Ghzmentioning

confidence: 98%

Development of a dual frequency (110/138 GHz) gyrotron for JT-60SA and its extension to an oscillation at 82 GHz

Kobayashia

Moriyama

Isayama

et al. 2015

EPJ Web of Conferences

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Abstract.A dual-frequency gyrotron, which can generate 110 GHz and 138 GHz waves independently, is being developed in JAEA to enable electron cyclotron heating (ECH) and current drive (ECCD) in a wider range of plasma discharge conditions of JT-60SA. Conditioning operation of the gyrotron toward 1 MW for 100 s, which is the target output power and pulse length for JT-60SA, is in progress without significant problems. Oscillations of 1 MW for 10 s and 0.5 MW for 198 s were obtained, so far, at both frequencies. Cooling water temperatures in the gyrotron and matching optics unit were saturated in the 198 s oscillation, and the observed maximum water temperature is sufficiently low. In addition to the above activity on the dualfrequency gyrotron development, an oscillation (0.3 MW for 20 ms) at 82 GHz was demonstrated as an additional frequency of the dual-frequency gyrotron. A possibility of the use of fundamental harmonic wave at 82 GHz in JT-60SA has been shown.

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“…Better homogeneity of the ICRF discharge, generation of the energetic neutrals bombarding the wall and the low electron temperature could contribute to the achieved result [12]. It should note that the homogeneity of ECWC at fundamental ECR was considerably improved by applying small horizontal magnetic field (B R /B T ≈2x10 -3 ) [28]. Analysis of the atomic mass number 3 (HD) release in TEXTOR during the RF conditioning pulse revealed a noticeable rise in the Q RR quantity at both, high and low BB T -fields (Fig.6).…”

Section: 5×10mentioning

confidence: 99%

ICRF Wall Conditioning: Present Status and Developments for Future Superconducting Fusion Machines

Lyssoivan¹,

Koch²,

Noterdaeme³

et al. 2009

AIP Conference Proceedings

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Abstract. ITER and future superconducting fusion machines need efficient wall conditioning techniques for routine operation in between shots in the presence of permanent high magnetic field for wall cleaning, surface isotope exchange and to control the in-vessel long term tritium retention. Ion Cyclotron Wall Conditioning (ICWC) based on the ICRF discharge is fully compatible and needs the presence of the magnetic field. The present paper focuses on the 18th Topical Conference on Radio Frequency Power in Plasmas, Gent, Belgium 2009, AIP Conference Proceedings 1187, Melville, New York, 2009 principal aspects of the ICWC discharge performance in large-size fusion machines: (i) neutral gas RF breakdown with conventional ICRF heating antennas, (ii) antenna coupling with low density (~10 17 m -3 ) RF plasmas and (iii) ICWC scenarios with improved RF plasma homogeneity in the radial and poloidal directions. All these factors were identified as crucial to achieve an enhanced conditioning effect (e.g. removal rates of selected "marker" masses). All the observed effects are analyzed in terms of RF plasma wave excitation/absorption and compared with the predictions from 1-D RF full wave and 0-D RF plasma codes. Numerical modeling and empirical extrapolation from the existing machines give good evidence for the feasibility of using ICWC in ITER with the main ICRF antenna.

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RF heated wall conditioning discharges in JT-60U

Cited by 20 publications

References 14 publications

Wall conditioning for ITER: Current experimental and modeling activities

Wall conditioning for ITER: Current experimental and modeling activities

Development of a dual frequency (110/138 GHz) gyrotron for JT-60SA and its extension to an oscillation at 82 GHz

ICRF Wall Conditioning: Present Status and Developments for Future Superconducting Fusion Machines

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