We demonstrate that a marginally unstable energetic particle population in a dissipative plasma can change globally due to the act of a single wave-particle resonance. The resonance serves as a seed for the continuous production of nonlinear holes and clumps, whose convective motion in phase-space results in substantial flattening of the fast particle distribution function. The holes and clumps can emerge recurrently without any particle source or collisional relaxation process that would

more »

... e the particle distribution function at the resonance. A bump-on-tail instability is considered as an example in a single-mode limit as well as in the quasilinear regime. The convective hole-clump transport tends to be more significant near the instability threshold than quasilinear diffusion.