Suppression of MARFEs by interferometric position control in the TEXTOR tokamak
Tokamak plasmas with a high average electron density may develop a strong radiating zone at the plasma boundary. When this zone is poloidally symmetric, the plasma is called detached, but it is often observed that the radiation is emitted mainly from only a small part of the poloidal circumference, and is predominantly located at the high field side. This phenomenon is called a MARFE, and discharges with MARFE activity are unstable and the density limit is usually reduced. The interferometric position control which is applied at the TEXTOR tokamak has proved to be a means for avoiding the development of MARFEs. A comparison between the interferometric and the conventional magnetic position control shows that MARFEs cannot be avoided by simply shifting the plasma away from the inner wall (where they appear) but that a dynamic response to in-out asymmetries in the electron density distribution is required.
Bibliographic Reference: Article: Proceedings of the 5th International Symposium on Laser-Aided Plasma Diagnostics (1991) pp. 98-102
Record Number: 199111654 / Last updated on: 1994-12-02
Original language: en
Available languages: en