This contribution presents the experimentally observed edge plasma evolution during limit cycle oscillations (LCO) measured with a new Langmuir and ball-pen multi-pin probe head at the COMPASS tokamak. The observed LCO regime modulates the intensity of density fluctuations δne, radial electric field Er and intensity of Dα emission with a frequency 3-5 kHz. The density fluctuations grow after Er decreases in strength which appears to be strongly correlated with the evolution of the pressure gradient ∂rp. The magnetic signature of the LCO shows a left-right asymmetry with propagation from the low to high field side. High-frequency (above 100 kHz) precursor-like oscillations are observed as well.
ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Condensed Matter Physics