Physics of the edge plasma and first wall in fusion devices: synergistic effects

Various synergistic effects resulting from plasma-wall interactions in magnetic fusion devices are considered. The crucial role of the first wall out-gassing processes in the recovery of pedestal density in the high-confinement mode of tokamak operation after giant type-I edge localized modes (ELMs) transient events as well as in the setting the ELM period is discussed. The shielding effects of vapor plasma formed during interactions of extremely large plasma heat fluxes with material surfaces are analyzed. The strongly non-linear impact of secondary electron emission from the divertor target on the incident plasma heat flux is discussed.