Sample records for jrve tiiu kamdron

  1. Improvement of a 500 keV heavy-ion-beam probe for JIPP T-IIU tokamak

    NASA Astrophysics Data System (ADS)

    Hamada, Y.; Kawasumi, Y.; Nishizawa, A.; Narihara, K.; Sato, K.; Seki, T.; Toi, K.; Iguchi, H.; Fujisawa, A.; Adachi, K.; Ejiri, A.; Hidekuma, S.; Hirokura, S.; Ida, K.; Kawahata, K.; Kojima, M.; Joong, K.; Kumazawa, R.; Kuramoto, H.; Liang, R.; Minami, T.; Sakakita, H.; Sasao, M.; Sato, K. N.; Tsuzuki, T.; Xu, J.; Yamada, I.; Watari, T.


    Several improvements in the high-voltage heavy-ion-beam probe (HIBP) are discussed. (1) It is clearly found that the precision slide mount of the detector plates 30° parallel to the base electrode is very effective for the determination of the in-plane entrance angle of the beam in the analyzer to estimate the error in the potential measurement. (2) A two-staged optical trap in the HIBP greatly reduced the effect of the UV radiation in the analyzer. (3) A multiple-plate detector up to 13 measurement points clearly showed the direction of the propagation of the turbulence and path-integral effects.

  2. 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.

  3. Development of an imaging vacuum-ultraviolet monochromator in the normal incidence region

    NASA Astrophysics Data System (ADS)

    Koog, J.; Iwasaki, K.; Sato, K.; Hamada, Y.; Toi, K.; JIPP T-IIU Group


    An imaging vacuum-ultraviolet monochromator has been developed to provide the space-resolved impurity line emissions from magnetically confined plasmas. With minor modifications of a commercial normal incidence monochromator, a pinhole entrance slit and a microchannel plate detector displaced away from the exit slit, the instrument performs two-dimensional spectroscopic observations in the wavelength range from 400 to 2000 Å. Ray tracing has been performed to understand the spatial imaging properties in the practical geometric configuration. The measured spatial resolution is about 0.5 and 1 mrad in dispersion and vertical plane, respectively, with the entrance slit of 0.1 mm width and height. The results of the testing experiments and the measurements carried out on the JIPP T-IIU tokamak plasma are presented and discussed.

  4. Pollen-inferred quantitative reconstructions of Holocene land-cover in NW Europe for the evaluation of past climate-vegetation feedbacks - The Swedish LANDCLIM project and the NordForsk LANDCLIM network

    NASA Astrophysics Data System (ADS)

    Gaillard, Marie-Jose; Sugita, Shinya; Rundgren, Mats; Smith, Benjamin; Mazier, Florence; Trondman, Anna-Kari; Fyfe, Ralph; Kokfelt, Ulla; Nielsen, Anne-Birgitte; Strandberg, Gustav


    of ca. 1o x 1o. The REVEALS estimates of the past cover of PFTs will be 1) compared with the outputs of the LPJ-GUESS (10 PFTs), a widely-used dynamic vegetation model and 2) used as an alternative to the LPJ-GUESS-simulated vegetation (3 PFTs) to run for the past the regional climate model RCA3 developed at the Rossby Centre, Norrköping, Sweden. The study will evaluate and further refine these models (RCA3 and LPJ-GUESS) using a data-model comparison approach that incorporates new syntheses of palaeoclimatic data as well. It will lead to new assessments of the possible effect of various factors on climate, such as deforestations and afforestations, and changes in vegetation composition and spatial patterns of land cover/land use. Refined climate models and empirical land-cover reconstructions will shed new light on controversial hypotheses of past climate change and human impacts, such as the "Ruddiman hypothesis". First maps of REVEALS estimates of plant functional types (PFTs) are now available for Sweden, Norway, Finland, Denmark, Estonia, Poland, Germany, The Czech Republic, Switzerland and Britain (see Mazier et al. C1.21 and Trondman et al. C1.22). Correlation tests show that the REVEALS estimates are robust in terms of ranking of the PFTs' abundance (see Mazier et al, C1.21). The LANDCLIM project and network are a contribution to the IGBP-PAGES-Focus 4 PHAROS programme on human impact on environmental changes in the past. The following LANDCLIM members are acknowledged for providing pollen records, for help with pollen databases, and for providing results to the project: Mihkel Kangur and Tiiu Koff (Univ. Tallinn, Tallinn); Erik Kjellström (SMHI, Norrköping), Anna Broström, Lena Barnekow and Thomas Persson (GeoBiosphere Science Centre, Lund University); Anneli Poska (Physical Geography and Ecosystems Analysis, Lund University); Thomas Giesecke (Albrecht-von-Haller-Institute for Plant Sciences, University of Göttingen), Anne Bjune and John Birks (Dept. of