- Diamond, PH
- Rosenbluth, MN
- Sanchez, E
- Hidalgo, C
- Milligen, BV
- Estrada, T
- Brañas, B
- Hirsch, M
- Hartfuss, HJ
- Carreras, BA
- et al.
We show that the modulational instability growth rate of zonal flows is determined directly from the quasilinear wave kinetic equation. We also demonstrate the relation between zonal-flow growth and the cross bispectrum of the high-frequency drift-wave-driven Reynolds stress and the low-frequency plasma potential by explicit calculation. Experimental measurements of the spatiotemporal evolution of the spectrum integrated bicoherence at the L → H transition near the edge shear layer indicate a modification in the nonlinear phase coupling, which might be linked to the generation of sheared E × B flows © 2000 The American Physical Society.