| Project/Area Number |
02680008
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
プラズマ理工学
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| Research Institution | Hiroshima University |
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Principal Investigator |
TAKIYAMA Ken Faculty of Engineering, Hiroshima University, Associate Professor, 工学部, 助教授 (40112180)
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| Co-Investigator(Kenkyū-buntansha) |
ODA Toshiatsu Faculty of Engineering, Hiroshima University, Professor, 工学部, 教授 (60034550)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1991: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1990: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Recombining Plasma / Plasma Spectrosopy / Population Inversion / 再結プラズマ |
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| Research Abstract |
The mechanism of formation of a recombining plasma as a short-wavelength laser medium by gas-contact cooling of a high temperature plasma was experimentally studied by means of the spectroscopic measurement.
1) Three kinds of helium plasmas with different initial electron temperatures (T_e) and densities (n_e) were produced by a Z-pinch gun, and each was injected into the hydrogen molecular gas. The time-resolved spectra and spatial distributions in emission lines of H. He and He_+ were observed by a spectroscopic system with a fast-gated multichannel detector.
2)The homogeneous mixingne of the plasma with hydrogen gas was achieved when the density of hydrogen gas exceeded the initial n_e of each plasma : At that gas density, the Stark broadening in H beta and He II 468.6nm lines showed that the atomic hydrogen felt, the same electron density as the He^+ ion did, and the spatial distribution of H beta line was also similar with that of Hell468.6nm line.
3)Cooling of electron temperature induced by the mixing was observed in each plasma. The final T_e after cooling strongly depended on the initial one.
4)The plasma cooled down less than 2eV was recognized to be in a recombining phase from the remarkable enhancement in the population density of the excited states of He^+ ion.
Thus, it was found that the formation of the recombining plasma was obviously dependent upon the initial plasma parameters, especially T_e. Further detailed investigation is to be proceeded in order to obtain the optimum plasma condition.
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