Time-dependent probability density function analysis of H-mode transitions

Abstract The first application of time-dependent probability density function (PDF) analysis to the L-H transition in fusion plasmas is presented. PDFs are constructed using Doppler Backscattering data perpendicular fluctuation velocity, , and turbulence from edge region DIII-D tokamak. These raw time-series sliced into millisecond-long sliding time-windows create PDFs. During transition, develop strong right tails, indicative turbulence-suppressing localised flows plasma edge; such features other subtle behaviours explored novel information geometry techniques. This letter examines applicability these techniques predict transitions investigate predator-prey self-regulation theories between velocity.