Confinement improvement by fluctuating input power

An interesting effect of the fluctuating input power on plasma confinement is reported. Specifically, the addition of the sinusoidal perturbation, Asin(wt), to constant power q₀ is shown to promote the confinement, leading to the L-H transition at a lower value of q₀, as compared to the case of constant q₀ without the sinusoidal perturbation. In general, higher amplitude (A) and lower frequency (w) are found to be more favorable for the L-H transition while an interesting linear relation between A and w leading to the L-H transition is established for different values of q₀.