AMPLIFICATION OF SYNCHROTRON RADIATION IN A STREAM-PLASMA SYSTEM

Employing the Einstein-coefficients approach, it is shown that synchrotron radiation can be amplified when a monoenergetic electron stream is gyrating in a helical path in the static magnetic field of a cold magnetoactive plasma. Errors appearing in recent literature concerning synchrotron radiation are pointed out. The frequency dependence of the amplification rate is discussed with the aid of some numerical examples. In the limiting case when the helical stream becomes a strictly rotating bunch, the result obtained is identical with that derived from the classical kinetic treatment.