The poloidal distribution of turbulence in the scrape-off layer (SOL) of the CASTOR tokamak is studied by means of a ring of 32 electric probes covering the whole perimeter of the poloidal cross section. Analysis of floating potential fluctuations in a SOL created in the top part of the machine by shifting the plasma downwards reveals a dominant periodic structure that propagates poloidally in the direction of the Er× B drift. Its poloidal mode number is found to be equal to the local safety factor q. Correlation and pulse propagation analyses show that this high m mode is a signature of a single long flute-like structure that is aligned with the magnetic field and snakes around the torus several times before terminating on the limiter.
All Science Journal Classification (ASJC) codes
- Nuclear Energy and Engineering
- Condensed Matter Physics
Devynck, P., Bonhomme, G., Martines, E., Stöckel, J., Van Oost, G., Voitsekhovitch, I., ... Hron, M. (2005). Spatially resolved characterization of electrostatic fluctuations in the scrape-off layer of the CASTOR tokamak. Plasma Physics and Controlled Fusion, 47(2), 269 - 280. https://doi.org/10.1088/0741-3335/47/2/005