Decreases as neutral pressure increases. Time Delayed Cross Correlation. Take two signals from fast magnetics p,q. Velocity Transient Response L-H Upper panels show example spectral fits. L-H transition triggered by sawtooth, which interrupts the measurement.
Values are roughly half what is deduced from the propagation measurements.
Better profile precision needed. Core and Edge Velocities Are modulated as plasma enters and leaves H-mode. Substantial time lag of core modulation relative to edge. If the propagation direction were toroidal, it would be supersonic. So are pedestal gradients.