Progress toward steady-state operation in LHD using electron cyclotron waves

Y. Yoshimura, S. Kubo, T. Shimozuma, H. Igami, H. Takahashi, S. Kobayashi, S. Ito, Y. Mizuno, Y. Takita, Y. Nakamura, K. Ohkubo, R. Ikeda, K. Ida, M. Yoshinuma, S. Sakakibara, T. Mutoh, K. Nagasaki, Hiroshi Idei, T. Notake

    Research output: Contribution to journalArticle

    11 Citations (Scopus)

    Abstract

    Trials of steady-state operation (SSO) in the Large Helical Device (LHD) were started when a continuous wave (cw) gyrotron with the output power up to 0.2 MW was introduced to the electron cyclotron heating (ECH) system on LHD in 2003. During the first trial of SSO in the seventh LHD experimental campaign in 2004, severe temperature increase on the waveguide transmission line and, as a result, intense pressure increase in the evacuated waveguide occurred, which terminated the operation at 756 s. Additional pumping sections and cooling structures on the transmission line worked well, allowing a 3900-s sustainment of plasma with ne=0.15 ×1019 m-3 and Te0 = 1.7 keV by 0.1 MW injection power in 2005. The improvement of the ECH system by introducing cw gyrotrons with higher power for further improvement of plasma performance in SSO is in progress. Investigations on electron cyclotron current drive (ECCD) physics have been advanced a few years after the proof of ECCD in LHD. By obliquely injecting secondharmonic X-mode EC waves in toroidal direction, stable current up to 5.5 kA is driven, which was evaluated as a difference in plasma currents of the co-and counter-ECCD discharges with 0.1-MW EC wave power. It takes a few seconds for the driven current to saturate. Change in profile of rotational transform by ECCD and profile of driven current density are investigated by use of motional Stark effect measurement. Peaked and localized driven current profile at the plasma core region was confirmed for on-axis second-harmonic ECCD discharges.

    Original languageEnglish
    Pages (from-to)551-559
    Number of pages9
    JournalFusion Science and Technology
    Volume58
    Issue number1
    DOIs
    Publication statusPublished - Jan 1 2010

    Fingerprint

    Electron devices
    Cyclotrons
    cyclotrons
    Electrons
    electrons
    Plasmas
    electron cyclotron heating
    Electric lines
    Waveguides
    transmission lines
    continuous radiation
    Gyrotrons
    profiles
    Stark effect
    Heating
    Wave power
    waveguides
    electron counters
    cyclotron resonance devices
    plasma currents

    All Science Journal Classification (ASJC) codes

    • Civil and Structural Engineering
    • Nuclear and High Energy Physics
    • Nuclear Energy and Engineering
    • Materials Science(all)
    • Mechanical Engineering

    Cite this

    Yoshimura, Y., Kubo, S., Shimozuma, T., Igami, H., Takahashi, H., Kobayashi, S., ... Notake, T. (2010). Progress toward steady-state operation in LHD using electron cyclotron waves. Fusion Science and Technology, 58(1), 551-559. https://doi.org/10.13182/FST58-551

    Progress toward steady-state operation in LHD using electron cyclotron waves. / Yoshimura, Y.; Kubo, S.; Shimozuma, T.; Igami, H.; Takahashi, H.; Kobayashi, S.; Ito, S.; Mizuno, Y.; Takita, Y.; Nakamura, Y.; Ohkubo, K.; Ikeda, R.; Ida, K.; Yoshinuma, M.; Sakakibara, S.; Mutoh, T.; Nagasaki, K.; Idei, Hiroshi; Notake, T.

    In: Fusion Science and Technology, Vol. 58, No. 1, 01.01.2010, p. 551-559.

    Research output: Contribution to journalArticle

    Yoshimura, Y, Kubo, S, Shimozuma, T, Igami, H, Takahashi, H, Kobayashi, S, Ito, S, Mizuno, Y, Takita, Y, Nakamura, Y, Ohkubo, K, Ikeda, R, Ida, K, Yoshinuma, M, Sakakibara, S, Mutoh, T, Nagasaki, K, Idei, H & Notake, T 2010, 'Progress toward steady-state operation in LHD using electron cyclotron waves', Fusion Science and Technology, vol. 58, no. 1, pp. 551-559. https://doi.org/10.13182/FST58-551
    Yoshimura Y, Kubo S, Shimozuma T, Igami H, Takahashi H, Kobayashi S et al. Progress toward steady-state operation in LHD using electron cyclotron waves. Fusion Science and Technology. 2010 Jan 1;58(1):551-559. https://doi.org/10.13182/FST58-551
    Yoshimura, Y. ; Kubo, S. ; Shimozuma, T. ; Igami, H. ; Takahashi, H. ; Kobayashi, S. ; Ito, S. ; Mizuno, Y. ; Takita, Y. ; Nakamura, Y. ; Ohkubo, K. ; Ikeda, R. ; Ida, K. ; Yoshinuma, M. ; Sakakibara, S. ; Mutoh, T. ; Nagasaki, K. ; Idei, Hiroshi ; Notake, T. / Progress toward steady-state operation in LHD using electron cyclotron waves. In: Fusion Science and Technology. 2010 ; Vol. 58, No. 1. pp. 551-559.
    @article{d11d0df7222e495c809bf585419dad1a,
    title = "Progress toward steady-state operation in LHD using electron cyclotron waves",
    abstract = "Trials of steady-state operation (SSO) in the Large Helical Device (LHD) were started when a continuous wave (cw) gyrotron with the output power up to 0.2 MW was introduced to the electron cyclotron heating (ECH) system on LHD in 2003. During the first trial of SSO in the seventh LHD experimental campaign in 2004, severe temperature increase on the waveguide transmission line and, as a result, intense pressure increase in the evacuated waveguide occurred, which terminated the operation at 756 s. Additional pumping sections and cooling structures on the transmission line worked well, allowing a 3900-s sustainment of plasma with ne=0.15 ×1019 m-3 and Te0 = 1.7 keV by 0.1 MW injection power in 2005. The improvement of the ECH system by introducing cw gyrotrons with higher power for further improvement of plasma performance in SSO is in progress. Investigations on electron cyclotron current drive (ECCD) physics have been advanced a few years after the proof of ECCD in LHD. By obliquely injecting secondharmonic X-mode EC waves in toroidal direction, stable current up to 5.5 kA is driven, which was evaluated as a difference in plasma currents of the co-and counter-ECCD discharges with 0.1-MW EC wave power. It takes a few seconds for the driven current to saturate. Change in profile of rotational transform by ECCD and profile of driven current density are investigated by use of motional Stark effect measurement. Peaked and localized driven current profile at the plasma core region was confirmed for on-axis second-harmonic ECCD discharges.",
    author = "Y. Yoshimura and S. Kubo and T. Shimozuma and H. Igami and H. Takahashi and S. Kobayashi and S. Ito and Y. Mizuno and Y. Takita and Y. Nakamura and K. Ohkubo and R. Ikeda and K. Ida and M. Yoshinuma and S. Sakakibara and T. Mutoh and K. Nagasaki and Hiroshi Idei and T. Notake",
    year = "2010",
    month = "1",
    day = "1",
    doi = "10.13182/FST58-551",
    language = "English",
    volume = "58",
    pages = "551--559",
    journal = "Fusion Science and Technology",
    issn = "1536-1055",
    publisher = "American Nuclear Society",
    number = "1",

    }

    TY - JOUR

    T1 - Progress toward steady-state operation in LHD using electron cyclotron waves

    AU - Yoshimura, Y.

    AU - Kubo, S.

    AU - Shimozuma, T.

    AU - Igami, H.

    AU - Takahashi, H.

    AU - Kobayashi, S.

    AU - Ito, S.

    AU - Mizuno, Y.

    AU - Takita, Y.

    AU - Nakamura, Y.

    AU - Ohkubo, K.

    AU - Ikeda, R.

    AU - Ida, K.

    AU - Yoshinuma, M.

    AU - Sakakibara, S.

    AU - Mutoh, T.

    AU - Nagasaki, K.

    AU - Idei, Hiroshi

    AU - Notake, T.

    PY - 2010/1/1

    Y1 - 2010/1/1

    N2 - Trials of steady-state operation (SSO) in the Large Helical Device (LHD) were started when a continuous wave (cw) gyrotron with the output power up to 0.2 MW was introduced to the electron cyclotron heating (ECH) system on LHD in 2003. During the first trial of SSO in the seventh LHD experimental campaign in 2004, severe temperature increase on the waveguide transmission line and, as a result, intense pressure increase in the evacuated waveguide occurred, which terminated the operation at 756 s. Additional pumping sections and cooling structures on the transmission line worked well, allowing a 3900-s sustainment of plasma with ne=0.15 ×1019 m-3 and Te0 = 1.7 keV by 0.1 MW injection power in 2005. The improvement of the ECH system by introducing cw gyrotrons with higher power for further improvement of plasma performance in SSO is in progress. Investigations on electron cyclotron current drive (ECCD) physics have been advanced a few years after the proof of ECCD in LHD. By obliquely injecting secondharmonic X-mode EC waves in toroidal direction, stable current up to 5.5 kA is driven, which was evaluated as a difference in plasma currents of the co-and counter-ECCD discharges with 0.1-MW EC wave power. It takes a few seconds for the driven current to saturate. Change in profile of rotational transform by ECCD and profile of driven current density are investigated by use of motional Stark effect measurement. Peaked and localized driven current profile at the plasma core region was confirmed for on-axis second-harmonic ECCD discharges.

    AB - Trials of steady-state operation (SSO) in the Large Helical Device (LHD) were started when a continuous wave (cw) gyrotron with the output power up to 0.2 MW was introduced to the electron cyclotron heating (ECH) system on LHD in 2003. During the first trial of SSO in the seventh LHD experimental campaign in 2004, severe temperature increase on the waveguide transmission line and, as a result, intense pressure increase in the evacuated waveguide occurred, which terminated the operation at 756 s. Additional pumping sections and cooling structures on the transmission line worked well, allowing a 3900-s sustainment of plasma with ne=0.15 ×1019 m-3 and Te0 = 1.7 keV by 0.1 MW injection power in 2005. The improvement of the ECH system by introducing cw gyrotrons with higher power for further improvement of plasma performance in SSO is in progress. Investigations on electron cyclotron current drive (ECCD) physics have been advanced a few years after the proof of ECCD in LHD. By obliquely injecting secondharmonic X-mode EC waves in toroidal direction, stable current up to 5.5 kA is driven, which was evaluated as a difference in plasma currents of the co-and counter-ECCD discharges with 0.1-MW EC wave power. It takes a few seconds for the driven current to saturate. Change in profile of rotational transform by ECCD and profile of driven current density are investigated by use of motional Stark effect measurement. Peaked and localized driven current profile at the plasma core region was confirmed for on-axis second-harmonic ECCD discharges.

    UR - http://www.scopus.com/inward/record.url?scp=77956686268&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=77956686268&partnerID=8YFLogxK

    U2 - 10.13182/FST58-551

    DO - 10.13182/FST58-551

    M3 - Article

    AN - SCOPUS:77956686268

    VL - 58

    SP - 551

    EP - 559

    JO - Fusion Science and Technology

    JF - Fusion Science and Technology

    SN - 1536-1055

    IS - 1

    ER -