| Budget Amount *help |
¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2000: ¥3,300,000 (Direct Cost: ¥3,300,000)
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| Research Abstract |
1) At first, we show the Hasegawa-Mima equation describing drift waves and drift-wave vortices and point out the analogy between drift waves and Rossby waves and the analogy between drift-wave vortices and Rossby-wave vortices. The theory of dipole drift-wave vortices and the computer-simulation results of mono-pole drift-wave vortices based on the Hasegawa-Mima equation are also described. On the base of these theoretical backgrounds, we tried to make an experiment of theoretically expected mono-pole drift-wave vortices.
2) Experimentally, we determined the dispersion relation of drift waves propagating perpen dicularilly to the density gradient and the magnetic field, and observed mono-pole drift-wave vortices for the first time. The observed mono-pole drift-wave vortices propagate with velocities of the drift-wave speed, being accompanied by the backward emission of short-w avelength wakes. Moreover, we detected their drift in the direction of density gradient in case of positive density perturbations, as observed in the computer simulation. In case of strong vortices, however, their behaviors are complicate and are difficult for us to fin d the physical mechanism.
3) We have found mono-pole drift-wave vortices for the first time, and clarified their characteristics. Drift waves and drift-wave vortices are specially important physical phenome na to control the confinement of fusion oriented plasmas. It is necessary to clarify the physics of drift waves and drift-wave vortices. Thus, still, we shall make efforts to get experimental data getting their physics clear.
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