A revised version of synchrotron radiation in a magnetized plasma

We analyze the propagation features of synchrotron radiation of a charge moving with a gyrating helix trajectory (3-dimensional) in a magnetoplasma. We found that a new factor (1+ cot ) should be included into the relevant spectrum radiation formulae and the usual relativistic factor has to be modified as, ifv <v_g, the radiative energy are more concentrated along the velocity of the moving charge; but ifv>v_g, the direction of maximum energy cone deviates from the direction of the moving charge.