In this talk, we would like to introduce how to describe <br /><br />
wave turbulence for nonlinearly and wealky interacting <br /><br />
despersive wave ensemble such as Hasselmann\\/s approach, <br /><br />
smooth cumulant method, random phase approximation, <br /><br />
and random phase and amplitude formalism which has been <br /><br />
developed most lately. And we also introduce recent <br /><br />
development in wave turbulence theory and application <br /><br />
to Alfven wave.