We demonstrate theoretically and numerically the zonal-flow/drift-wave
feedback mechanism for the LH transition in an idealised model of plasma
turbulence driven by a small scale instability. Zonal flows are generated by a
secondary modulational instability of the modes which are directly driven by
the primary instability. The zonal flows then suppress the small scales thereby
arresting the energy injection into the system, a process which can be
described using nonlocal wave turbulence theory. Finally, the arrest of the
energy input results in saturation of the zonal flows at a level which can be
estimated from the theory and the system reaches stationarity without damping
of the large scales.Comment: 4 pages, 2 figure
