The role of a new mode coupling effect (plasma-maser) in space plasma physics is reviewed. The new maser effect, the idea that the resonant electrons with the low-frequency mode can amplify the high-frequency mode, does not require population inversion of electrons. The generation mechanisms of ULF modulated ELF emissions, auroral kilometric radiation, chorus related electrostatic bursts, whistler mode in the solar wind, and type III solar radio bursts are studied based on plasma-maser effect. The forced plasma-maser interaction model reduces to a conservative Lotka-Volterra system. A chaotic behavior of the forced Lotka-Volterra system is obtained. The new mode coupling process has potential importance in attempting to interpret numerous astrophysical radio phenomena.