Abstract
The four-beam correlation method has a potential of measuring fine-scale fluctuations locally. In the method, many lines of sight are measured and the coherences among them are calculated. As a proof of principle experiment, a visible fluctuation measurement system has been fabricated and applied to the TST-2 spherical tokamak plasma. Using this system, fluctuations were measured and high-frequency components (100 ± 12.5kHz) were analyzed. Because of a long parallel correlation length, local information was not obtained directly. However, comparison of the experimental results and those of a model calculation suggests that (i) the fluctuating emission is relatively localized in the peripheral region of the plasma, (ii) the perpendicular correlation length is of the order of 1 cm, while the parallel one is much longer than it and (iii) the magnetic field angle in the peripheral region agrees with that estimated from magnetic measurements.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 7557-7563 |
| Number of pages | 7 |
| Journal | Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers |
| Volume | 42 |
| Issue number | 12 |
| DOIs | |
| State | Published - Dec 2003 |
| Externally published | Yes |
All Science Journal Classification (ASJC) codes
- General Engineering
- General Physics and Astronomy
Keywords
- Magnetic field angle
- Perpendicular correlation length
- Spherical tokamak
- Visible fluctuations