| Project/Area Number |
10680467
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
プラズマ理工学
|
|---|
| Research Institution | National Institute for fusion Science |
|---|
Principal Investigator |
TANAKA Masayoshi y. National Institute for fusion Science, Associate Professor, 大型ヘリカル研究部, 助教授 (90163576)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
吉村 信次 核融合科学研究所, 大型ヘリカル研究部, 助手 (50311204)
|
|---|
| Project Period (FY) |
1998 – 1999
|
| Project Status |
Completed (Fiscal Year 1999)
|
| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1998: ¥1,300,000 (Direct Cost: ¥1,300,000)
|
|---|
| Keywords | directional Langmuir probe / plasma flow / symmetry / ion saturation current / macroscopic flow / convection / plasma production / 磁場効果 / 大規模耕造 / 流れ / プラズマ / 流れ場 / マッハ数 / 流速測定 / EXBドリフト / ポテンシャル計測 |
|---|
| Research Abstract |
Measuring plasma flow velocity is of primary importance to study large-scale and self-organized structures in plasmas, and is also necessary to understand the dynamical behavior of boundary plasma in confinement systems. So far, many works have been done on the flow velocity measurement using directional Langmuir probes (DLP) or Mach probes. However, directional Langmuir probes is considered to be unsuitable for the determination of perpendicular flow velocity.
Although conventional theories on DLP deal with parallel flow cases or ion-unmagnetized cases, the results are merely adopted for the determination of perpendicular flow velocity without carefully examining the effect of magnetic field on the directional probe current. Thus, the application of the conventional theory to perpendicular flow measurement has not been justified yet.
We both experimentally and theoretically demonstrate that ion flow velocity at an arbitrary angle with respect to the magnetic field can be measured with a directional Langmuir probe. We have developed t the general theory of ion current on DLP based on the symmetry property of the effects of magnetic field and flow, and shown that the effect of magnetic field on the DLP current can be exactly cancelled. The general relation between flow velocity and DLP currents is obtained, and experimentally confirmed its validity under both unmagnetized and magnetized conditions. It is verified that flow velocity in arbitrary directions can be measured with a DLP.
Using a calibrated DLP, we have measured macroscopic flow structure in an ECR plasma, and found that there is a large scale convection extended to the whole size of the chamber.
|
