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Furukane, Utaro; Sato, Kuninori; Oda, Toshiatsu.
Nagoya Univ. (Japan). Inst. of Plasma Physics1988
Nagoya Univ. (Japan). Inst. of Plasma Physics1988
AbstractAbstract
[en] High potentiality leading to rapid cooling of a high temperature plasma is investigated in a gas contact cooling method in which the effect of finite time for mixing the plasma and the contact gas is considered. The calculation has shown that the cooling is much more rapid than the radiative loss cooling and that the gain per unit length of the HeII 164 nm is ∼2 cm-1 for the laser oscillation under an optimum condition. Possibility of realizing a shorter wavelength laser is also discussed in a plasma with higher charge number Z. (author)
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Jul 1988; 33 p
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Kato, Takako; Masai, Kuniaki; Sato, Kuninori.
Nagoya Univ. (Japan). Inst. of Plasma Physics1985
Nagoya Univ. (Japan). Inst. of Plasma Physics1985
AbstractAbstract
[en] Several line intensities of OIV and OV ions were measured on the JIPPT-IIU tokamak plasma along the central-chord by using a grazing-incidence monochromator. The contribution of the inner subshell ionization is significant in the JIPPT-IIU tokamak plasma. This is a characteristic phenomenon in the ionizing plasma with the electron temperature higher than the ionization temperature where the actual ion ratio exists in ionization equilibrium. This process increases the level populations of metastable states. The intensity Isub(i) is thus increased. Calculations show that the intensity Isub(r) is also increased by 10 % by the inner subshell ionization in a plasma of Tsub(e) = 100 eV and nsub(e) = 1012 cm-3. Spectroscopic observation of OIV and OV ions is usable for diagnosis of the electron density in tokamak plasmas. (Mori, K.)
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Feb 1985; 16 p
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[en] Leading members of the Lyman series of He II emitted from a high-density helium plasma have been measured by the use of the Rare-gas Photoelectron Counter which is based on the energy analysis of photoelectrons liberated by XUV radiation. Stationary population inversion between low lying levels of He+ is confirmed in a recombining plasma which is interacting with neutral helium. The ratio n2/g2:n3/g3:n4/g4:n5/g5 is found to be 1:0.6:1.1:1.2. A method of determining the electron temperature, the electron density and the ion density from the recombination continua is described. Collisional and recombination processes can explain reasonably the observed level populations. (auth.)
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Journal of the Physical Society of Japan; v. 43(3); p. 1027-1033
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[en] Population inversion, which occurs in a recombining plasma when a stationary plasma is brought into contact with a neutral gas, is surveyed. The mechanism of the population inversion in a recombining plasma is discussed with an emphasis on atomic processes. (author)
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[en] The experiment on the forbidden lines from the highly ionized atoms in tokamak plasma was carried out at Princeton Large Torus (PLT) Facility. This paper is a review of this experiment and its background. The study of the forbidden lines from highly ionized atoms concerns the diagnostics of plasma temperature. Some forbidden lines have long wave-length and are useful for the measurement of ion temperature. The intensity of the forbidden lines of the atoms with large atomic numbers is sufficiently strong to measure, and the impurities from limiters and the walls of vessels are identified by the measurement of forbidden lines. The forbidden lines of Fe and Ti were observed by the discharge experiment with stainless steel limiters and Ti limiters. When a carbon limiter was used at PLT, the spectrum of Fe ions was remarkably reduced. The impurity injection experiment has been developed to obtain the basic data of forbidden lines in a tokamak. (Kako, T.)
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Bunko Kenkyu; ISSN 0038-7002; ; v. 32(3); p. 157-165
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[en] A simple spectrometer is designed in which a transmission grating is adopted to disperse vacuum ultraviolet radiation and space resolution is achieved by using an aperture of the grating as a one-dimensional analog of a pin hole camera. Wave length resolution is calculated to be less than 5A. (author)
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Narihara, Kazumichi; Hasegawa, Mitsuru; Tomita, Yukihiro; Tsuzuki, Tetsuya; Sato, Kuninori; Mohri, Akihiro.
Nagoya Univ. (Japan). Inst. of Plasma Physics1983
Nagoya Univ. (Japan). Inst. of Plasma Physics1983
AbstractAbstract
[en] It was experimentally demonstrated that Astron-Spherator configuration is formed by injecting a pulsed relativistic electron beam in a toroidal device SPAC-VI with external toroidal and vertical magnetic fields. A plasma is confined in the extended magnetic region produced by a slender core of current carrying energetic electrons. This configuration continued for 40 ms without fatal instabilities. (author)
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Jan 1983; 24 p
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[en] To estimate the ion temperature of plasma using Doppler broadening with a low-resolution monochromator, a convolution-fitting method was proposed. This method utilizes the information of the slit function of the monochromator to improve the effective resolution. It consists of a convolution calculation of trial functions and the slit function, and a fitting of the result with a measured line spectrum. A model experiment was carried out to demonstrate the usefulness of the method. The measured lines were C III 2296.8 A and C V 2270.9 A from JIPP T-IIU Tokamak. The slit function was obtained by measuring Hg I 2656.5 A line from a mercury lamp. Applying the method to these lines, effective resolution was improved by a factor of about seven. (author)
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Japanese Journal of Applied Physics. Part 1, Regular Papers and Short Notes; ISSN 0021-4922; ; CODEN JAPNDE; v. 34(3); p. 1668-1672
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[en] The shape of the cross section of the electron beam of an electron synchrotron observed photographically (spot) is discussed in relation to the distribution function for the amplitude and the phase of the betatron oscillation and also that for the coordinates of a particle and the inclination of its orbit to the equilibrium orbit. It is found that the probability density that particles move on the equilibrium orbit is zero, when the observed spot has a non-cusped finite intensity at its center. For example, a gaussian distribution for the spot intensity results from the rayleighan distribution for the amplitude. In this case the full half-width of the spot is given by 4(ln 2/π)sup(1/2) < A>, where < A> is the mean amplitude of the betatron oscillation. (auth.)
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Japanese Journal of Applied Physics; v. 17(5); p. 917-927
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[en] A high potentiality of plasma cooling and its mechanism are theoretically revealed for a helium plasma which comes into contact with hydrogen molecular gas in the TPD-I machine. The stationary population inversion between the levels n=2 and 3 of the He+ ion, which is due to mixing of the stationary high-temperature helium plasma and the hydrogen molecular gas, is simulated and discussed in comparison with cooling due to the mixing of the plasma and the atomic hydrogen gas. The calculation also shows that the gain per unit length of the He II 164 nm line is ∼2 cm-1 for the laser oscillation under optimum initial helium plasma (Te∼30 eV and ne∼3.5 x 1016 cm-3) contacted with hydrogen molecular gas at a pressure of 0.1 Torr. (author)
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