Intense intermittent radiation has been observed regularly in EAST plasmas. The duration of radiation bursts is with a characterization time of a few microseconds. The radiation is very intense, with an equivalent radiation temperature higher than the electron cyclotron emission by a few orders of magnitude. An electron density threshold exists to terminate the bursts, and it is strongly dependent on the toroidal magnetic field. The radiation frequency f is at the plasma frequency, and the frequency bandwidth is very narrow (∼1.5 MHz FWHM, ). The fine structure of the spectrum in the frequency domain has been observed, and the frequency spacing is around 3 MHz. The cavity modes model is capable of explaining the radiation frequency and the frequency spacing. However, a quantitative and complete description of this phenomenon is still lacking.
Intense millimetre wave bursts from plasmas well conditioned with lithium in the Tokamak Fusion Test Reactor