1997 Fiscal Year Final Research Report Summary
Study of Internal Structure of a Field-Reversed-Configuration Plasma
| Project/Area Number |
08680540
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nuclear fusion studies
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| Research Institution | NIHON UNIVERSITY |
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Principal Investigator |
NOGI Yasuyuki Nihon University, College of Science and Technology, Professor, 理工学部, 教授 (90059569)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMAMURA Shin Nihon University, College of Science and Technology, Assistant, 理工学部, 助手 (00059627)
SUZUKI Kiyomitsu Nihon University, College of Science and Technology, Lecturer, 理工学部, 専任講師 (10216369)
TAKAHASHI Tsutomu Nihon University, College of Science and Technology, Lecturer, 理工学部, 専任講師 (50179496)
HAMADA Shigeo Nihon University, College of Science and Technology, Professor, 理工学部, 教授 (10059058)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Thermonuclear Fusion / High Beta Plasma / Theta Pinch / Field Reversed Configuration / Magnetic Confinement / Bremsstrahlung / Internal Structure / Effective Ion Charge Number |
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| Research Abstract |
A purpose of the present project is to study experimentally macro instabilities occurred in a Field-Reversed Configuration (FRC) plasma It is well known that onsets of a rotational instability and an internal tilt instability give a severe damage to an FRC.As the deformation of the plasma due to the former instability can be easily observed. it has been investigated by many theorist and experimentarist from the early phase of the FRC research. It was found about ten years ago that the deformation is controlled by applying a multipole field. On the other hand, since die latter instability happens inside the separatrix, it is hard to observe by using simple diagnostic methods. According to this obstacle, the speed of the study about this instability is very slow.
We developed a diagnostic system having 36 optical channels to investigate the structure of the plasma inside the separatrix. Each channel consists of a collimator with a convex lens, an optical fiber, an optical wavelength filter and a photomultiplier tube. They are calibrated by using a standard lamp. These collimators are arranged around a vacuum vessel which is constructed by a transparent quartz tube. This optical system detects bremsstrahlung from the plasma on a given plane.
Following results are obtained from the data analyzed by an Abel inversion and a computer tomography methods. 1. Intensity profile of the radiation at a toroidal plane of the FRC is similar to a square density profile of the rigid rotor model except lack of die axial symmetry. 2. Vividly axial expansion and compression of the plasma is observed in a poloidal plane. A lot of the plasma moves toward both ends of the FRC at the expansion phase. 3. It has been modeled that the toroidal cross section of the plasma is elliptically deformed by the onset of the rotational instability. However, it looks like that of a dumbbell from the present measurement.
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Research Products
(20 results)
