This Letter reports on observed interplay between beam-driven modes of sweeping
frequency (chirping modes) and transitions to the enhanced global confinement regime
(H-mode) and back to the low confinement regime (L-mode) in the spherical tokamak
ST40. The H-modes of plasma confinement are identified from decreased intensity of
Dα signal and f…
Spherical Tokamaks (STs) with a high normalised plasma pressure parameter are promising alternative pathways for net gain magnetic fusion reactors. Toroidal Alfvén eigenmodes (TAEs) excited via wave-particle resonances by fusion-born alpha-particles are of major concern for burning deuterium-tritium (D-T) plasmas in magnetic fusion as TAEs ca…
