1993 Fiscal Year Final Research Report Summary
Study on a Current Channel Shrinkage and a Heating Enhancement Due to a Maqnetic Compressionof ULQ Plasmas
| Project/Area Number |
04402049
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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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 | University of Tokyo |
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Principal Investigator |
OGAWA Yuichi University of Tokyo, Dept.of Quantum Engineering and Systems Science, Associate Professor, 工学部, 助教授 (90144170)
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| Co-Investigator(Kenkyū-buntansha) |
SHINOHARA Shunjiro University of Kyushu, Interdisciplinary Graduate School of Engineering Sciences,, 大学院・総合理工学研究科, 助教授 (10134446)
TOYAMA Hiroshi University of Tokyo, Dept.of Physics, Professor, 理学部, 教授 (50023718)
MORIKAWA Junji University of Tokyo, Dept.of Quantum Engineering and Systems Science, Technical, 工学部, 教務職員 (70192375)
YOSHIDA Zensho University of Tokyo, Dept.of Quantum Engineering and Systems Science, Associate, 工学部, 助教授 (80182765)
INOUE Nobuyuki University of Tokyo, Dept.of Quantum Engineering and Systems Science, Professor, 工学部, 教授 (60023719)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Plasma / Nuclear Fusion / ULQ / VLQ / Magnetic compression / Magnetic fluctuations / H_<alpha> signal / Ion anomalous heating / Dynamo electric field |
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| Research Abstract |
The magnetic compresseion has been applied for a Ultra-low-q (ULQ) plasma with a safety factor q (a) of less than unity, where the toroidal magetic field B_t was increased from 0.1 T to 0.3 T.During the magnetic compression phase, the increases of the loop voltage and magnetic fluctuations have been observed, indicating the enhancement of the resistance anomaly. This might be accounted for a poloidal electric field induced by the rapid increase of the toroidal magnetic field, the direction of which is opposite to the incident dynamo electric field. H_<alpha> signals have drastically suppressed during the magnetic compression, accompanied by the shrinkage of the plasma column with a few centimenter.
Just after the magnetic compression the plasma current begins to increase, and the loop voltage and magentic fluctuations are kept at low levels during this phase. Compared with the scaling of resistance anomaly for ULQ plasmas, the plasma resistance of this phase is quite low, and more stable and quiescent ULQ plasmas have been realized by applying the magnetic compression for ULQ plasmas. This stable ULQ configuration terminates when the rational surface appears at the plasma surface, accompanied by the increase of magnetic fluctuations and the anomalous ion heating. It is found that the magnetic compression is very powerful to introduce an externally-induced poloidal electric field and to understand the role of the dynamo electric field in ULQ plasmas.
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