1992 Fiscal Year Final Research Report Summary
Development of a Power-Modulated Laser System with Long Pulse Duration and Its Application to Plasma Diagnostics
| Project/Area Number |
02452272
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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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 | School of Engineering,Nagoya University |
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Principal Investigator |
TSUKISHIMA Takashige School Engineering, Department of Electrical Engineering,Prof., 工学部, 教授 (20023020)
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| Co-Investigator(Kenkyū-buntansha) |
SASAKI Koichi School of Engineering,Department of Electrical Engineering,Res. Assoc., 工学部, 助手 (50235248)
NAGATSU Masaaki School of Engineering,Department of Electrical Engineering,Assoc. Prof., 工学部, 助教授 (20155948)
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| Project Period (FY) |
1990 – 1992
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| Keywords | power-modulated laser / injection locking / excitation of electrostatic waves / driven scattering method / electrostatic ion cyclotron wave / efficiency of the wave excitation / theoretical analysis / computer simulation |
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| Research Abstract |
The objective of the present study is to prove the principles of the driven scattering method which has been proposed as a novel scheme for high temperature plasma diagnostics. In the driven scattering, a power-modulated laser beam is injected into the plasma to excite electrostatic waves. Certain plasma parameters can be evaluated from the dispersion character of the excited waves.
In 1990, a power-modulated TEA CO_2 laser system was developed. Two-mode pulse injection locking scheme was adopted and a power-modulated (the modulation frequency of 30MHz, 10J-class outputs with long pulse durations of the order of 1mus were obtained with high probability.
In 1991, electrostatic ion cyclotron waves were excited in a laboratory plasma by making use of the power-modulated laser system developed in 1990. Langmuie probes were used to detect the plasma waves. A newly developed numerical filter having a narrow bandwidth was used to extract the wave signal from noisy background. The dispersion character of the excited waves was consistent with the dispersion relation of the electrostatic ion cyclotron wave.
In 1992, the wave amplitude obtained in the experiment was compared with those predicted by a theoretical analysis and computer simulation. The wave amplitude obtained experimentally roughly agreed with the theoretical value within an order of magnitude, while the simulation result agreed well with the theoretical value.
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