Coherent edge fluctuation measurements in H-mode discharges on JFT-2M

Yoshihiko Nagashima, K. Shinohara, K. Hoshino, A. Ejiri, K. Tsuzuki, T. Ido, K. Uehara, H. Kawashima, K. Kamiya, H. Ogawa, Takuma Yamada, S. Shiraiwa, S. Ohara, Y. Takase, N. Asakura, N. Oyama, T. Fujita, S. Ide, H. Takenaga, Y. KusamaY. Miura

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Abstract

Results of coherent edge fluctuation measurements using three diagnostics (a reciprocating Langmuir probe, a two channel O-mode reflectometer, and fast magnetic probes) in H-mode discharges on JFT-2M are presented. In discharges in which a high recycling steady (HRS) H-mode phase is obtained through a transient phase with slightly enhanced Dα intensity, two types of coherent fluctuations are observed. The higher frequency mode (around 300kHz) is the high frequency mode (HFM) observed in the HRS H-mode (Kamiya K et al 2003 9th IAEA Tech. Meeting H-mode Workshop Topic B-14). The lower frequency mode has a frequency of around 80kHz. The HFM is detected by a Langmuir probe over a wide region in the SOL, as well as by the reflectometer and magnetic probes. However, the HFM is not detected by the higher frequency (38 GHz) channel of the reflectometer after the HRS transition, suggesting that the HFM is not located deeply inside the plasma. The 80 kHz mode is detected by both channels of the reflectometer and by a Langmuir probe, but not by magnetic probes, suggesting that it is an electrostatic mode. In contrast to the HFM, the 80kHz mode is detected by the Langmuir probe only near the separatrix during the transient phase, which leads to either the HRS phase or the ELMy phase, and is similar to the fluctuations reported in Shinohara K et al (1998 J. Plasma Fusion Res. 74 607).

Original languageEnglish
JournalPlasma Physics and Controlled Fusion
Volume46
Issue number5 SUPPL. A
DOIs
Publication statusPublished - Jan 1 2004

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Langmuir probes
Reflectometers
Recycling
Plasmas
reflectometers
electrostatic probes
recycling
magnetic probes
Electrostatics
Fusion reactions

All Science Journal Classification (ASJC) codes

  • Nuclear Energy and Engineering
  • Condensed Matter Physics

Cite this

Coherent edge fluctuation measurements in H-mode discharges on JFT-2M. / Nagashima, Yoshihiko; Shinohara, K.; Hoshino, K.; Ejiri, A.; Tsuzuki, K.; Ido, T.; Uehara, K.; Kawashima, H.; Kamiya, K.; Ogawa, H.; Yamada, Takuma; Shiraiwa, S.; Ohara, S.; Takase, Y.; Asakura, N.; Oyama, N.; Fujita, T.; Ide, S.; Takenaga, H.; Kusama, Y.; Miura, Y.

In: Plasma Physics and Controlled Fusion, Vol. 46, No. 5 SUPPL. A, 01.01.2004.

Research output: Contribution to journalArticle

Nagashima, Y, Shinohara, K, Hoshino, K, Ejiri, A, Tsuzuki, K, Ido, T, Uehara, K, Kawashima, H, Kamiya, K, Ogawa, H, Yamada, T, Shiraiwa, S, Ohara, S, Takase, Y, Asakura, N, Oyama, N, Fujita, T, Ide, S, Takenaga, H, Kusama, Y & Miura, Y 2004, 'Coherent edge fluctuation measurements in H-mode discharges on JFT-2M', Plasma Physics and Controlled Fusion, vol. 46, no. 5 SUPPL. A. https://doi.org/10.1088/0741-3335/46/5A/043
Nagashima, Yoshihiko ; Shinohara, K. ; Hoshino, K. ; Ejiri, A. ; Tsuzuki, K. ; Ido, T. ; Uehara, K. ; Kawashima, H. ; Kamiya, K. ; Ogawa, H. ; Yamada, Takuma ; Shiraiwa, S. ; Ohara, S. ; Takase, Y. ; Asakura, N. ; Oyama, N. ; Fujita, T. ; Ide, S. ; Takenaga, H. ; Kusama, Y. ; Miura, Y. / Coherent edge fluctuation measurements in H-mode discharges on JFT-2M. In: Plasma Physics and Controlled Fusion. 2004 ; Vol. 46, No. 5 SUPPL. A.
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abstract = "Results of coherent edge fluctuation measurements using three diagnostics (a reciprocating Langmuir probe, a two channel O-mode reflectometer, and fast magnetic probes) in H-mode discharges on JFT-2M are presented. In discharges in which a high recycling steady (HRS) H-mode phase is obtained through a transient phase with slightly enhanced Dα intensity, two types of coherent fluctuations are observed. The higher frequency mode (around 300kHz) is the high frequency mode (HFM) observed in the HRS H-mode (Kamiya K et al 2003 9th IAEA Tech. Meeting H-mode Workshop Topic B-14). The lower frequency mode has a frequency of around 80kHz. The HFM is detected by a Langmuir probe over a wide region in the SOL, as well as by the reflectometer and magnetic probes. However, the HFM is not detected by the higher frequency (38 GHz) channel of the reflectometer after the HRS transition, suggesting that the HFM is not located deeply inside the plasma. The 80 kHz mode is detected by both channels of the reflectometer and by a Langmuir probe, but not by magnetic probes, suggesting that it is an electrostatic mode. In contrast to the HFM, the 80kHz mode is detected by the Langmuir probe only near the separatrix during the transient phase, which leads to either the HRS phase or the ELMy phase, and is similar to the fluctuations reported in Shinohara K et al (1998 J. Plasma Fusion Res. 74 607).",
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T1 - Coherent edge fluctuation measurements in H-mode discharges on JFT-2M

AU - Nagashima, Yoshihiko

AU - Shinohara, K.

AU - Hoshino, K.

AU - Ejiri, A.

AU - Tsuzuki, K.

AU - Ido, T.

AU - Uehara, K.

AU - Kawashima, H.

AU - Kamiya, K.

AU - Ogawa, H.

AU - Yamada, Takuma

AU - Shiraiwa, S.

AU - Ohara, S.

AU - Takase, Y.

AU - Asakura, N.

AU - Oyama, N.

AU - Fujita, T.

AU - Ide, S.

AU - Takenaga, H.

AU - Kusama, Y.

AU - Miura, Y.

PY - 2004/1/1

Y1 - 2004/1/1

N2 - Results of coherent edge fluctuation measurements using three diagnostics (a reciprocating Langmuir probe, a two channel O-mode reflectometer, and fast magnetic probes) in H-mode discharges on JFT-2M are presented. In discharges in which a high recycling steady (HRS) H-mode phase is obtained through a transient phase with slightly enhanced Dα intensity, two types of coherent fluctuations are observed. The higher frequency mode (around 300kHz) is the high frequency mode (HFM) observed in the HRS H-mode (Kamiya K et al 2003 9th IAEA Tech. Meeting H-mode Workshop Topic B-14). The lower frequency mode has a frequency of around 80kHz. The HFM is detected by a Langmuir probe over a wide region in the SOL, as well as by the reflectometer and magnetic probes. However, the HFM is not detected by the higher frequency (38 GHz) channel of the reflectometer after the HRS transition, suggesting that the HFM is not located deeply inside the plasma. The 80 kHz mode is detected by both channels of the reflectometer and by a Langmuir probe, but not by magnetic probes, suggesting that it is an electrostatic mode. In contrast to the HFM, the 80kHz mode is detected by the Langmuir probe only near the separatrix during the transient phase, which leads to either the HRS phase or the ELMy phase, and is similar to the fluctuations reported in Shinohara K et al (1998 J. Plasma Fusion Res. 74 607).

AB - Results of coherent edge fluctuation measurements using three diagnostics (a reciprocating Langmuir probe, a two channel O-mode reflectometer, and fast magnetic probes) in H-mode discharges on JFT-2M are presented. In discharges in which a high recycling steady (HRS) H-mode phase is obtained through a transient phase with slightly enhanced Dα intensity, two types of coherent fluctuations are observed. The higher frequency mode (around 300kHz) is the high frequency mode (HFM) observed in the HRS H-mode (Kamiya K et al 2003 9th IAEA Tech. Meeting H-mode Workshop Topic B-14). The lower frequency mode has a frequency of around 80kHz. The HFM is detected by a Langmuir probe over a wide region in the SOL, as well as by the reflectometer and magnetic probes. However, the HFM is not detected by the higher frequency (38 GHz) channel of the reflectometer after the HRS transition, suggesting that the HFM is not located deeply inside the plasma. The 80 kHz mode is detected by both channels of the reflectometer and by a Langmuir probe, but not by magnetic probes, suggesting that it is an electrostatic mode. In contrast to the HFM, the 80kHz mode is detected by the Langmuir probe only near the separatrix during the transient phase, which leads to either the HRS phase or the ELMy phase, and is similar to the fluctuations reported in Shinohara K et al (1998 J. Plasma Fusion Res. 74 607).

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