  The creation and subsequent evolution of marginally-unstable modes have been
observed in a wide range of fusion devices. This behaviour has been
successfully explained, for a single frequency shifting mode, in terms of
phase-space structures known as a `hole' and `clump'.
  Here, we introduce stochasticity into a 1D kinetic model, affecting the
formation and evolution of resonant modes in the system. We find that noise in
the fast particle distribution or electric field leads to a shift in the
asymptotic behaviour of a chirping resonant mode; this noise heuristically maps
onto microturbulence via canonical toroidal momentum scattering, affecting hole
and clump formation. The profile of a single bursting event in mode amplitude
is shown to be stochastic, with small changes in initial conditions affecting
the lifetime of a hole and clump. As an extension to the work of Lang and Fu,
we find that an intermediate regime exists where noise serves to decrease the
effective collisionality, where microturbulence works against pitch-angle
scattering.
