Chaotic behavior of the radiation field in the magnetically insulated transmission line oscillator.

In terms of the nonlinear coupled equations that describe the evolution of the radiation field and electrons motion in the magnetically insulated transmission line oscillator, the nonlinear instabilities existing in the process of the interaction between the electron beam and field are analyzed. It is shown that the development of the instability leads to the appearance of the nonlinear behavior of the radiation field. (1) In the soft nonlinear regime in which the radiation field is characterized by the periodic limit cycle, the power spectrum is discrete and the sideband is not symmetric around the carrier frequency; in the hard nonlinear regime in which the radiation field is characterized by the chaotic oscillation, the power spectrum is continuous and the spectral components with larger amplitude distribute in the low frequency region. (2) The threshold current at which the limit cycle or chaotic oscillation starts occurring is a function of the detuning. The appearance of the nonlinear unsteady states may be accelerated and inhibited by controlling detuning. (3) The arising of the limit cycle oscillation and chaotic behavior of the radiation field is easier in a magnetically insulated transmission line oscillator than in a traveling wave tube amplifier.