Sample records for merje tikk tiiu

  1. Radiation Loss and Impurity Abundance during ICRF Heating in the JIPP T-IIU Tokamak

    NASA Astrophysics Data System (ADS)

    Ogawa, Isamu; Kawahata, Kazuo; Ogawa, Yuichi; Watari, Tetsuo; Noda, Nobuaki; Masai, Kuniaki; Kako, Eiji; Tanahashi, Shyugo; Toi, Kazuo; Fujita, Junji


    Spectroscopic and bolometric measurements with spatial and temporal resolution show that large radiation loss brings about the decrease in electron and ion temperature and plasma energy. Regarding emissivity in a core plasma, the result by bolometric measurements well agrees with that estimated from impurity abundance and radiative cooling rates. Carbon limiters have an effect to suppress the radiation loss for Ohmic plasma, but is insufficient for ICRF heated plasma. The main contribution to radiation loss may be attributed to Fe impurity released from the ICRF antennae, the Faraday shield and vacuum vessel. By making carbonization, the Fe impurity is suppressed to a low level (nFe/ne˜0.03%) and the radiation loss is reduced to Prad/(POH+Pfr)˜20%. This clearly supported by the observation of Zeff (3.9→1.2).

  2. Turnaround Schools and the Leadership They Require

    ERIC Educational Resources Information Center

    Leithwood, Kenneth; Strauss, Tiiu


    "Turnaround Schools and the Leadership They Require" was commissioned by the Canadian Education Association (CEA) in 2006. The research, conducted by Kenneth Leithwood and Tiiu Strauss, was a two-year study of Ontario schools identified as in need of "turnaround" meaning that a significant improvement in school achievement was required. The study…

  3. Quick profile-reoriganization driven by helical field perturbation for suppressing tokamak major disruptions

    NASA Astrophysics Data System (ADS)

    Yamazaki, K.; Kawahata, K.; Ando, R.; Matsuoka, K.; Hirokura, S.; Kitagawa, S.; Mohri, A.; Tanahashi, S.; Taniguchi, Y.; Toi, K.


    Disruptive behavior of magnetic field configuration leading to tokamak major disruption is found to be controlled by a mild mini-disruption which is induced by the compact external modular multipole-field coils with m=3/n=2 dominant helical field component in the JIPP T-IIU tokamak. This mini-disruption ergodizes the m=2/n=1 magnetic island quickly but mildly and then prevents the profile of electron temperature from flattening. This quick profile-reorganization is effective to avoid the two-step disruption (pre- and major disruptions) responsible for the catastrophic current termination.