MODIFIED SELF-CONSISTENT NONLINEAR SIMULATION OF CYCLOTRON AUTORESONANCE MASER-AMPLIFIERS

Since the electron cyclotron auto-resonance maser (CARM) is operated w ith the wave refractive index being very close to unity, a little vari ation of the refractive index in the CARM calculations might be crucia l. Therefore, a modified self-consistent one-dimensional nonlinear mod el was developed by exactly setting the evolving wave refractive index and keeping all second-order terms to examine the inadequacy induced by the simplification of the earlier one-dimensional models. Compariso ns of the numerical results obtained by the earlier models and the mod ified model for a CARM amplifier reveal that the inadequate relaxation of the limited azimuthal and axial bunching region for electrons to l ose energy in the earlier models was the main reason for the overestim ate of the linear gain and the saturated efficiency for the fast (the slow) wave branch with initial refractive index n(0) < 1 (n(0) > 1). H owever, the earlier model with fixed n(0) = 1 is an excellent approxim ation whatever linear or saturated state is considered. The efficiency dependence of a CARM amplifier on some basic operating parameters was reexamined by the modified formulations. (C) 1998 American Institute of Physics.