The amplification mechanism of extra-ordinary mode radiation in the presence of kinetic Alfvén wave turbulence driven by an electron beam is studied. It is shown that plasma maser process may be responsible for the amplification of the extra-ordinary mode through up-conversion of turbulent energy via nonlinear wave particle interaction. The relevance of this investigation to space plasmas is discussed.

The present contribution tries to find a scientific answer to the question of stability of an equilibrium plasma sheath in a colloidal plasma system under external gravity effect. A model equilibrium of hydrodynamical character has been discussed on the basis of quasi-hydrostatic approximation of levitational condition. It is found that such an equilibrium is highly unstable to a modified-ion acoustic wave with a conditional likelihood of linear driving of the so-called acoustic mode too. Thus, it is reported (within fluid treatment) that a plasma-sheath edge in a colloidal plasma under external gravity effect could be highly sensitive to the acoustic turbulence. Its consequential role on possible physical mechanism of Coulomb phase transition has been conjectured. However, more rigorous calculations as future course of work are required to corroborate our phenomenological suggestions.