We present a detailed derivation of the Bessel function factor in the gain/pendulum expressions for a planar wiggler FEL. We show three individually nonnegligible corrections to the standard derivation of Colson (IEEE J. Quantum Electron. QE-17 (8) (1981) 1417). All three corrections however cancel and give the "standard" Bessel function factor of Colson. The gain of a sectional planar wiggler, is investigated for a variation in the deflection parameter, K, in one of its sections. Results produced are compared with and are in good agreement with experiment. © 1987.
|Number of pages||5|
|Journal||Nuclear Inst. and Methods in Physics Research, A|
|Publication status||Published - 1 Sep 1987|