A lot of physical processes, after the electron beam was injected into the plasma edge, are analyzed in details. In particular, we analyzed the formations of the parallel current layer and the radial negative electrical field which makes the plasma confinement transition from the low mode to the high mode,i.e,LH thransition.It was confirmed that the density of the injected electron beam exceed the fixed value, the threshold value for LH thransition,the LH transition was triggered.