An Estimation method for an unknown covariance in cross-section adjustment based on unbiased and consistent estimator

Maruyama, Shuhei; Endo, Tomohiro*; Yamamoto, Akio*

Journal of Nuclear Science and Technology, 60(11), p.1372 - 1385, 2023/11

https://doi.org/10.1080/00223131.2023.2203707

Role of low order rational -values in the ITB events in JT-60U reverse shear plasmas

Neudatchin, S. V.*; Takizuka, Tomonori; Hayashi, Nobuhiko; Isayama, Akihiko; Shirai, Hiroshi; Fujita, Takaaki; Kamada, Yutaka; Koide, Yoshihiko; Suzuki, Takahiro

Nuclear Fusion, 44(9), p.945 - 953, 2004/09

https://doi.org/10.1088/0029-5515/44/9/002

The formation of internal transport barriers (ITBs) near q=3 surfaces in normal shear (NrS) discharges of JT-60U is known. In reverse shear (RS) JT-60U plasmas, the role of q minimum (qmin) equal to 3.5,3,2.5,2 was not obvious for ITB formation. ITB-events (non-local confinement bifurcations inside and around ITB) are found in various NrS and RS plasmas. Under sufficient heating power, ITB-events are seen at rational and not rational values of qmin. The space-time evolution of Te and Ti is similar, suggesting the same mechanism of Te and Ti transport. The temporal formation of strong ITB under passing of qmin=3 (after periodical improvements and degradations via ITB-events) in RS mode is presented. Under smaller power, ITB-events are observed only at rational values of qmin. In a weak RS shot, abrupt rise of Te is seen at qmin=3.5, while more cases of Ti rise are observed. The difference of Te and Ti evolutions seen regularly under the low power, suggests decoupling of Te and Ti transport.

Establishment of X-ray reference fields for performance tests of radiation measuring instruments based on international standard(ISO4037-1)

Shimizu, Shigeru; Zhang, Q.; Kajimoto, Yoichi; Kawasaki, Tomokatsu; Fujii, Katsutoshi

JAERI-Tech 2003-095, 52 Pages, 2004/01

JAERI-Tech-2003-095.pdf:2.66MB

The International Standards ISO4037-1 of the International Organization for Standardization widely applied in the world to construct X-ray reference fields for performance tests of radiation measuring instruments. The application of the current JAERI's X-ray reference field constructed in accordance with the Japanese Standards should be limited for domestic purposes becase of the characterization technique different from the International Standards. Therefore,for application to international performance tests, X-ray reference fields in the narrow,wide and high air-kerma series based on the International Standards were established using the medium-hard X-ray generator of the Facility of Radiation Standards(FRS), JAERI. This report presents quality characterization, estimation of X-ray spectra of each dose units of the new FRS's fields,and comparison of the qualities and the X-ray spectra to those of the ISO's. The FRS's qualities show good agreement with ISO's: the reference fields should serve for performance tests for international radiation protection purposes.

Inner layer problem for ideal MHD modes in a toroidal system

Tokuda, Shinji

Proceedings of 30th EPS Conference on Controlled Fusion and Plasma Physics (CD-ROM), 4 Pages, 2003/00

When we solve the eigenvalue problem associated with the two-dimensional Newcomb equation, we can identify the stability of a tokamak plasma against ideal MHD perturbations. The eigenvalue problem does not give the physical growth rate when the plasma is unstable. However, we can determine the growth rate by constructing a dispersion relation that gives the relation between the growth rate and the eigenvalue. It is expected that the dispersion relation provides an effective and fast method of stability analysis of MHD modes close to the marginal stability against ideal MHD perturbations, and the relation can be extended for non-ideal MHD modes close to the marginal stability.

Singular point analysis

Tokuda, Shinji

Purazuma, Kaku Yugo Gakkai-Shi, 78(9), p.913 - 924, 2002/09

https://doi.org/10.1585/jspf.78.913

An introductory review is given on recent developments in the methods for stability analysis of a toroidally confined plasma. Emphasis is put on the perturbation analysis of a magnetohydrodynamic system that has the marginally stable state as a terminal point of continuous spectra. We address ourselves to the asymptotic matching method pertinent to such a problem. The Newcomb equation and inner-layer equations are essential ingredients in the methods and the numerical methods for solving them are discussed.

Development of whole energy absorption spectrometer for decay heat measurement

Maekawa, Fujio; Wada, Masayuki*; Ikeda, Yujiro

Nuclear Instruments and Methods in Physics Research A, 450(2-3), p.467 - 478, 2000/08

https://doi.org/10.1016/S0168-9002(00)00301-6

no abstracts in English

A New approach to the two-dimensional Newcomb equation

Tokuda, Shinji

Journal of Accelerator and Plasma Research, 5(1), p.87 - 108, 2000/00

no abstracts in English

Subroutine library for error estimation of matrix computation, Ver.1.0

*; *; *

JAERI-Data/Code 99-016, 183 Pages, 1999/03

JAERI-Data-Code-99-016.pdf:4.87MB

no abstracts in English

Measurement of Q-values of La isomers

Kojima, Yasuaki*; Asai, Masato*; Osa, Akihiko; Koizumi, Mitsuo; Sekine, Toshiaki; Shibata, M.*; *; Kawade, Kiyoshi*

Applied Radiation and Isotopes, 49(7), p.829 - 834, 1998/00

https://doi.org/10.1016/S0969-8043(97)00303-5

no abstracts in English

Eigenvalue method for the outer-region matching data in resistive MHD stability analysis

Tokuda, Shinji; *

Purazuma, Kaku Yugo Gakkai-Shi, 73(10), p.1141 - 1154, 1997/10

http://ci.nii.ac.jp/naid/110003826781

no abstracts in English