Inclusion of spacecharge effects with Maxwell's equations in the singleparticle analysis of freeelectron lasers
Abstract
A selfconsistent analysis is presented of the behavior of the electromagnetic field and the modulated electron beam in the singleparticle representation in a freeelectron laser taking into account spacecharge effects in the stronginteraction regime. A set of coupled equations describing the interrelations between the electron beam and the radiation field in the smallsignal limit is derived from the Lorentz force equations for the electronradiation interaction and the Maxwell equations of field generation by the modulated electron beam, and the equations are solved by decoupling the equations into a sixthorder differential equation for the modulation functions. It is found that the electron beam modulation is described by a threewave solution. The variation of the radiation field has a more complicated structure, with field variations of the interferencelike and exponentiallike types depending on frequency mismatch, plasma frequency and pumping strength. Plasma resonance is observed at high electron densities in an oscillator due to singlepass gain maximization. The analysis is then applied to a specific example resembling a traveling wave tube.
 Publication:

IEEE Journal of Quantum Electronics
 Pub Date:
 August 1981
 DOI:
 10.1109/JQE.1981.1071304
 Bibcode:
 1981IJQE...17.1387S
 Keywords:

 Electron Beams;
 Free Electron Lasers;
 Maxwell Equation;
 PlasmaElectromagnetic Interaction;
 Space Charge;
 Electron Energy;
 Electron Pumping;
 Lorentz Force;
 Magnetohydrodynamic Stability;
 Plasma Waves;
 Poisson Equation;
 Self Consistent Fields;
 Traveling Wave Tubes;
 Lasers and Masers