著者

片山 弘造 山田 知穂 桂井 誠

出版者

社団法人 プラズマ・核融合学会

雑誌

核融合研究 (ISSN:04512375)

巻号頁・発行日

vol.51, no.4, pp.297-302, 1984-05-20 (Released:2011-03-04)

参考文献数

9

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Relaxation processes toward the lower energy states in spheromak configurations were studied by means of three dimensional magnetohydrodynamic simulations. For the initial conditions, two cases of equilibrium states were given and the temporal evolutions of the instabilities were investigated in the nonlinear regime. In the first case, which has a high q-profile (1.7 at the magnetic axis), the poloidal flux amplification was observed through the development of a m=1, n=1 mode. This process can be explained by the Kadomtsev internal disruption model. In the second case, which has a low q-profile (0.12 at the magnetic axis), magnetic flux conversion from the poloidal to the toloidal direction toward the Taylor minimum energy state was observed through the development of a m=1, n=4 kink mode. It is expected that this process is related to the self-reversal mechanism in a reversed field pinch.

著者

渡邉 國彦

出版者

社団法人 プラズマ・核融合学会

雑誌

プラズマ・核融合学会誌 (ISSN:09187928)

巻号頁・発行日

vol.80, no.5, pp.374-377, 2004 (Released:2004-09-22)

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Large-scale simulation research is the most important and effective method to reveal the physical mechanisms in the complex systems such as fusion plasma. The current state of the development and history of the supercomputer system of Theory and Computer Simulation Center of National Institute for Fusion Science are summarized and the concept of the next generation simulator is introduced.

著者

渡辺 健二 宇山 忠男

出版者

社団法人 プラズマ・核融合学会

雑誌

核融合研究 (ISSN:04512375)

巻号頁・発行日

vol.60, no.3, pp.163-192, 1988-09-20 (Released:2011-03-04)

参考文献数

68

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Progress of the confinement study of Spheromak plasma is reviewed from the view point of APPLICATION OF TOKAMAK PHYSICS. Energy confinement time is around 0.1ms. Accuracy of comparison between theory and experiment was fairly improved by introduction of 3D simulation in two instability cases.

著者

小野 靖

出版者

社団法人 プラズマ・核融合学会

雑誌

プラズマ・核融合学会誌 (ISSN:09187928)

巻号頁・発行日

vol.80, no.11, pp.921-923, 2004 (Released:2005-07-14)

参考文献数

8

被引用文献数

1 1

---

High-beta ST research is motivated by its high normalized current Ip/aBT0 achievable at a low aspect ratio and its direct access to second stability for ballooning modes. Key issues for the high-beta ST sustainment are profile control for ballooning/ current-driven kink stabilities and positioning of the conductive wall for mode suppression. ST termination by resistive wall modes (RWM) revealed that velocity shear is a useful tool for the better stability.

著者

鳥居 寛之 黒田 直史 檜垣 浩之 船越 亮 大島 永康

出版者

社団法人 プラズマ・核融合学会

雑誌

プラズマ・核融合学会誌 (ISSN:09187928)

巻号頁・発行日

vol.80, no.12, pp.1012-1021, 2004 (Released:2005-07-14)

参考文献数

46

---

Antiprotons produced by a proton synchrotron are decelerated and cooled first to 5.3 MeV by stochastic cooling and electron cooling in the Antiproton Decelerator (AD) ring, then to 111 keV by a Radio Frequency Quadrupole Decelerator (RFQD). After the deceleration of the RFQD, antiprotons are degraded by thin PET foils and injected into the Multi-Ring electrode Trap(MRT). Electrons are preloaded in the MRT to cool the antiprotons to subelectron volt energy region. Ramping up the trapping potential slowly allows ultra-slow antiprotons of 10-500eV to be extracted from the strong magnetic field region. Positrons from 22Na are cooled by N2 gas or by electrons to form a cold positron plasma. A rotating electric field is used to radially compress the plasma.

著者

横山 昌弘 井沢 靖和 兜 秀昭 山中 千代衛

出版者

社団法人 プラズマ・核融合学会

雑誌

核融合研究 (ISSN:04512375)

巻号頁・発行日

vol.16, no.4, pp.261-264, 1966 (Released:2011-03-04)

参考文献数

6

著者

横山 昌弘 井沢 靖和 兜 秀昭 山中 千代衛

出版者

社団法人 プラズマ・核融合学会

雑誌

核融合研究 (ISSN:04512375)

巻号頁・発行日

vol.16, no.6, pp.509-512, 1966 (Released:2011-03-04)

参考文献数

9

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When an intense laser light passes through a plasma, a small fraction of it is scattered by free electrons. Measurements of the intensity and the spectral distribution of the scattered light from the shocked plasma has been used to determine the electron density and the electron temperature behind the reflected shock waves. Rayleigh scattering signal from one atmospheric pressure air was used as.a measure to evaluate the magnitude of Thomson scattering signal from the shocked plasm, In our experiments the electron densities behind the reflected shock wave at initial pressure of Ar 1 mmHg were determined as. about 1016 cm-3, which were in good agreement with a calculated value by shock theory. By assuming a plasma parameter α=0.85, theoretical curve accords very well with the measured spectral distribution of the scattered light. In this case the electron, temperature behind the refledted shock wave at initial pressure of Ar 0.4 mmHg was 23, 000oK.

著者

小西 哲之

出版者

社団法人 プラズマ・核融合学会

雑誌

プラズマ・核融合学会誌 (ISSN:09187928)

巻号頁・発行日

vol.78, no.11, pp.1157-1164, 2002 (Released:2005-12-08)

参考文献数

9

被引用文献数

1

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Based on the fundamental approach for safety of ITER, a possible extension of it to assure the safety of fusion power plant was considered. Although the entire an alysis and licensing preparation are specific for ITER, its methodology which takes full advantage of the inherent features of fusion is expected to be applied to the fundamental logic of fusion power plants. Both energy and radioactive source terms that could be potential hazards are typically operative for a number of days rather than for a year, as in the case of fission. The major differences from the test reactor ITER were identified as the power blanket, coolant loop, and a generator train that will hold high temperature and a considerable amount of tritium. It is anticipated that the tritium inventory and most of the tritium plant would essentially be same as those for ITER, tritium recovery and removal from the blanket loop will dominate the fusion power plant tritium systems. Such a tritium system will actively remove tritium at a daily throughput of the order of plant inventory. This feature suggests that no dedicated off-normal systems are needed to assure the safety of the fusion plant in terms of environmental tritium release.

著者

吉田 聡

出版者

社団法人 プラズマ・核融合学会

雑誌

プラズマ・核融合学会誌 (ISSN:09187928)

巻号頁・発行日

vol.78, no.7, pp.641-645, 2002 (Released:2005-12-08)

参考文献数

35

被引用文献数

1

---

Applications of inductively coupled plasma mass spectrometry (ICP-MS) to the determination of long-lived radionuclides in environmental samples were summarized. In order to predict the long-term behavior of the radionuclides, related stable elements were also determined. Compared with radioactivity measurements, the ICP-MS method has advantages in terms of its simple analytical procedures, prompt measurement time, and capability of determining the isotope ratio such as240Pu/239Pu, which can not be separated by radiation. Concentration of U and Th in Japanese surface soils were determined in order to determine the background level of the natural radionuclides. The 235U/238U ratio was successfully used to detect the release of enriched U from reconversion facilities to the environment and to understand the source term. The 240Pu/239Pu ratios in environmental samples varied widely depending on the Pu sources. Applications of ICP-MS to the measurement of I and Tc isotopes were also described. The ratio between radiocesium and stable Cs is useful for judging the equilibrium of deposited radiocesium in a forest ecosystem.

著者

小林 史歩

出版者

社団法人 プラズマ・核融合学会

雑誌

プラズマ・核融合学会誌 (ISSN:09187928)

巻号頁・発行日

vol.78, no.7, pp.678-684, 2002 (Released:2005-12-08)

参考文献数

16

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Gamma-raybursts (GRBs) are the most explosive events after the big bang. For a few seconds a GRB be comes the brightest object in the Universe, overshining the rest of the Universe combined. Clearly this reflects extreme conditions that are fascinating and worth exploring. GRB observations were recently revolutionised by the discovery of the delayed X-ray emission, called ”afterglow”. These observations revealed that the deceleration of relativistically expanding fireballs causes GRBs. I discuss special relativistic effects that play an important role in the fireball model.

著者

河島 信樹 長友 信人 栗木 恭一

出版者

社団法人 プラズマ・核融合学会

雑誌

核融合研究 (ISSN:04512375)

巻号頁・発行日

vol.31, no.6, pp.244-253, 1974 (Released:2011-03-04)

参考文献数

4

著者

石川 裕

出版者

社団法人 プラズマ・核融合学会

雑誌

プラズマ・核融合学会誌 (ISSN:09187928)

巻号頁・発行日

vol.79, no.8, pp.759-764, 2003 (Released:2005-09-28)

参考文献数

4

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This paper introduces an overview of the SCore cluster system software running on the Linux operating system. SCore utilizes PC cluster hardware efficiently and provides its users a high-performance parallel programming environment. This paper also presents brief installation information for the end-users.

著者

小西 哲之 時松 宏治

出版者

社団法人 プラズマ・核融合学会

雑誌

プラズマ・核融合学会誌 (ISSN:09187928)

巻号頁・発行日

vol.78, no.11, pp.1192-1198, 2002 (Released:2005-12-08)

参考文献数

7

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Energy model analysis estimates the significant contribution of fusion in the latter half of the century under the global environment constraints if it will be successfully developed and introduced into the market. The total possible economical impact of fusion is investigated from the aspect of energy cost savings, sales, and its effects on Gross Domestic Products. Considerable economical possibility will be found in the markets for fusion related devices, of currently developing countries, and for synthesized fuel. The value of fusion development could be evaluated from these possible economic impact in comparison with its necessary investment.

著者

飛田 健次 小西 哲之 時松 宏治 西尾 敏 日渡 良爾

出版者

社団法人 プラズマ・核融合学会

雑誌

プラズマ・核融合学会誌 (ISSN:09187928)

巻号頁・発行日

vol.81, no.11, pp.875-891, 2005 (Released:2007-01-12)

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This section describes the future of fusion energy in terms of its impact on the global energy supply and global warming mitigation, the possible entry scenarios of fusion into future energy market, and innovative technologies for deploying and expanding fusion's share in the market. Section 5.1 shows that fusion energy can contribute to the stabilization of atmospheric CO2 concentration if fusion is introduced into the future energy market at a competitive price. Considerations regarding fusion's entry scenarios into the energy market are presented in Sec. 5.2, suggesting that fusion should replace fossil energy sources and thus contribute to global warming mitigation. In this sense, first generation fusion power plants should be a viable energy source with global appeal and be so attractive as to be employed in developing countries rather than in developed countries. Favorable factors lending to this purpose are fusion's stability as a power source, and its security, safety, and environmental frendliness as well as its cost-of-electricity. The requirements for core plasma to expand the share of fusion in the market in the latter half of this century are given in Sec.5.3, pointing out the importance of high beta access with low aspect ratio and plasma profile control. From this same point of view, innovative fusion technologies worthy of further development are commented on in Sec. 5.4, addressing the high temperature blanket, hydrogen production, high temperature superconductors, and hot cell maintenance.

著者

山内 通則 西谷 健夫 西尾 敏

出版者

社団法人 プラズマ・核融合学会

雑誌

プラズマ・核融合学会誌 (ISSN:09187928)

巻号頁・発行日

vol.80, no.11, pp.952-954, 2004 (Released:2005-07-14)

参考文献数

2

---

Considering the geometrical characteristics of tokamak reactors with low aspect ratio, a basic neutronics strategy was derived to construct an inboard structure mainly for neutron shielding and to produce enough tritium in the outboard blanket. The designs for optimal inboard shield were surveyed and the necessary thickness was estimated to make the neutron flux sufficiently low on the super-conducting magnet. In addition, the outer blanket designs were studied to attain a tritium breeding ratio (TBR) sufficiently large for a self-sustaining fusion reactor on the basis of advanced fusion reactor materials.

著者

西尾 敏

出版者

社団法人 プラズマ・核融合学会

雑誌

プラズマ・核融合学会誌 (ISSN:09187928)

巻号頁・発行日

vol.80, no.1, pp.14-17, 2004 (Released:2004-06-16)

参考文献数

13

被引用文献数

1

---

SiC⁄SiC composite is a promising structural material candidate for fusion power cores and has been considered internationally in several power plant studies. It offers safety advantages arising from it slow induced radioactivity and afterheat, and the possibility of high efficiency of energy conversion through high temperature operation. The latest SiC⁄SiC-based power core design studies are summarized, and the key SiC⁄SiC parameters affecting the performance of power core components are high lighted.

著者

小野 靖

出版者

社団法人 プラズマ・核融合学会

雑誌

プラズマ・核融合学会誌 (ISSN:09187928)

巻号頁・発行日

vol.79, no.2, pp.144-151, 2003 (Released:2005-09-28)

参考文献数

15

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Recently, high-beta operations of Spherical Tokamak (ST) have received increased attention due to the compatibility achieved between high-beta and a long confinement time. In addition to the high normalized current I/aB achievable at a low aspect ratio, an important advantage of high-beta ST is its direct access to second stability for ideal ballooning modes. The mega-ampere class experiments, NSTX and MAST, renewed the record beta values up to βT˜35%, increasing confinement time up to τE˜0.1 sec. Small-scale experiments produced the second-stable STs with diamagnetic toroidal field /absolute minimum-B by transforming oblate FRCs. Major issues for the second stable STs are achieving a stable startup/ profile control for kink and the ballooning stabilities and a concrete approach to high-ratio pressure driven currents .

著者

松田 七美男

出版者

社団法人 プラズマ・核融合学会

雑誌

プラズマ・核融合学会誌 (ISSN:09187928)

巻号頁・発行日

vol.78, no.2, pp.144-154, 2002 (Released:2005-12-08)

参考文献数

7

被引用文献数

2 2

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This article introduces how to process and visualize scientific data with using ”Gnuplot” which is freely available plotting utility from the Internet. Not only a simple example of drawing a single plot on a page but also advanced feature of handling data stream and communication to the external application is explained.

著者

菱川 明栄

出版者

社団法人 プラズマ・核融合学会

雑誌

プラズマ・核融合学会誌 (ISSN:09187928)

巻号頁・発行日

vol.80, no.9, pp.742-748, 2004 (Released:2005-07-14)

参考文献数

18

被引用文献数

2 1

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The structures of rotational and vibrational energy levels and the term symbols to classify different electronic states are described for diatomic molecules. Different classes of parity, (+/−), (e/f) and (s/a), associated with each rovibronic level are discussed. The transition probability, the Franck-Condon factors, the Hönl-London factors and the transition moments of electronic transitions and their selection rules are described.