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The linear theory of electromagnetic radiation from a high-power backward-wave-oscillator (BWO), travelling-wave-tube (TWT) with plasma-filled, sinusoidally corrugate waveguide driven by an intense relativistic electron beam (IREB) has been derived and analysed numerically. A general dispersion relation is presented for analysing a plasma-filled corrugate waveguide immersed in magnetized plasma in this paper. It is shown that the linear theory developed here is in good agreement with the previous work.

A general dispersion equation of a partially filled plasma corrugated waveguide immersed in a finite magnetic field is presented. When the guiding magnet B0→∞ or 0, this equation can be reduced to the results obtained in previous works.

A new type of partial-dielectric-loaded helical groove slow-wave structure (SWS) for millimetre wave travelling wave tube (TWT) is presented in this paper. The radio-frequency characteristics including the dispersion properties, the longitudinal electric field distribution and the beam-wave coupling impedance of this structure are analysed. The results show that the dispersion of the helical groove circuit is weakened, the phase velocity is reduced and the position of the maximum Ez is moved from the mouth to the inside of the groove after partially filling the dielectric materials in the helical groove SWS. Therefore, the dielectric-loaded helical groove SWS is suitable for a multi-beam TWT with broad band and high gain.

Theoretical study of electromagnetic wave pumped ion-channel free-electron laser (EPIC-FEL) is presented. The physical mechanism responsible for the generation of coherent radiation in the EPIC-FEL is described and the fundamental role of the ponderomotive wave in bunching and trapping the beam is emphasized. The dispersion relation of the EPIC-FEL has been obtained and growth rates are calculated for different parameters. It shows that EPIC-FEL has a very bright future.

A new hybrid maser instability is described for the case of wave interactions for an electron-beam (e-beam) propagating through an ion channel in a plasma-filled waveguide immersed in a finite axial magnetic field. Complete linear theoretical formulation and sample numerical calculations are presented. The significant features of this new hybrid instability are discussed.

A linear theory and a more general dispersion relation of electromagnetic radiation from a magnetized plasma-filled backward wave oscillator with sinusoidally corrugated slow-wave structure driven by a solid intense relativistic electron beam have been given. The comparisons show good agreement with the previous works when B0 → ∞ and ωb=0 from this dispersion relation.

This two-part paper presents the first complete, generalized basic theoretical formulation for electron beam-wave interactions in a plasma-filled (corrugated or smooth-walled) waveguide immersed in a finite magnetic field. The general interaction and dispersion equations of the longitudinal and transverse interactions in both smooth and corrugated magnetized plasma-filled waveguides (MPWs) are formulated. Our approach differs from that of previous investigators in that we begin by first deriving the dispersion relation of an MPW and then using the resulting electromagnetic fields, which embody the plasma effects, as the basis field vectors. We then investigate the underlying interactions with a superimposed electron-beam in a variety of microwave device configurations. For example, we examine plasma Cherenkov radiation, the plasma-filled travelling-wave-tube/backward-wave-oscillator (TWT/BWO), the plasma-filled electron cyclotron resonance maser (ECRM), and other beam-wave interactions including those involving ion-channels. Some possible new interactions in a magnetized plasma-filled waveguide (MPW) are proposed. A detailed discussion and analysis of the important physical role of the plasma background are given. Many interesting features of beam-wave interactions in an MPW are pointed out, three of them being most essential. One is that transverse interactions are always accompanied by longitudinal interactions. The second is that the magnetized plasma itself is strongly involved in the interaction mechanisms via an additional component of the field. The third interesting feature is that the plasma-filled ECRM prefers to operate at high cyclotron harmonics. The first part of this two-part paper presents formulations using a fluid model for both the plasma and the beam. It also includes a detailed treatment of the physical effects of the ion channel that is formed in the plasma by an intense electron beam. Part II extends the analyzes by retaining a fluid treatment for the plasma-fill but substituting a kinetic theory treatment for the electron beam. This kinetic theory model should be used when the velocity spread of the beam's electrons must be taken into account. The theory presented in both parts of this paper is based upon the "given field" approach that has been widely used successfully in science and technology, in particular in microwave electronics. In both parts of the paper, sample numerical calculations are also presented in order to illustrate the physics.

For pt.I see ibid., vol.28, no.6, p.2135-51 (2000) Building upon the theoretical foundations presented in Part I of this paper, the kinetic theory of electron-beam-wave interactions in a magnetized plasma-filled waveguide (MPW) is presented in this second part. This kinetic theory treatment is more generally applicable to cases of less-intense electron-beams (Montgomery and Tidman, 1964). The dispersion relations for longitudinal and transverse interactions, in both smooth and corrugated waveguides, are all derived by using kinetic theory to model the e-beam dynamics. This includes kinetic theory treatments of the plasma filled electron cyclotron resonance maser (ECRM) and a combination of Cherenkov-cyclotron resonance phenomena. It is important to note that in an MPW, transverse interactions (e.g., ECRM interactions) are always coupled with longitudinal interactions. Using the kinetic treatment is essential for studying the ECRM because its energy conversion mechanism is based on azimuthal phase bunching and finite Larmor radius effects. The dispersion relation that we derive shows that the presence of a plasma-fill tends to increase the growth rate of the waveguide mode ECRM instability.

From the fluid model, the plasma is an isotropic medium. First, it is obtained that the microwave field in a cylindrical cavity filled with plasma, where the microwave comes from vacuum cylindrical waveguide. Coupling with fluid equations for the electron and ion motion, the microwave discharge courses are calculated. The results show that the curves of ion and electron density distributions are similar as the curves of electric field intensity distribution. Also, a critical electron density is exist. Above this density, microwave field will damp rapidly, this makes the gas ionization mainly happening on the surface.

The structure of cylindrical cavity coupling with rectangular waveguides through large apertures on the cavity’s sidewall is studied in detail. The fields in the cavity is properly expanded by derived mode functions. By making reasonable approximation of the boundary conditions, the process of derivation and the formation of the characteristic equation is greatly simplified. The characteristic equation and model coefficients are obtained. The reliability of the derived characteristic equation is tested. Numerical results of characteristic frequency and quality factor changing with dimensions of coupling holes are given.

Starting from general transmission line equations with an electron beam source, a self-consistent nonlinear theoretical model for a complex cavity gyrotron with gradual transitions is presented in this paper. The model accounts for mode coupling in the transition region of the complex cavity. The interaction between the electron beam and H/sub 61/-H/sub 62/ RF field in the complex cavity for a third-harmonic gyrotron is simulated; many calculations are carried out under different cavity dimensions and electron beam parameters.

The use of a background plasma in a dielectric Cherenkov maser can effectively increase the efficiency and the microwave output power of the device. Here, the effect of the longitudinal uniform magnetic field on the wave-beam interaction of the plasma-filled dielectric Cherenkov maser is examined by solving the beam-plasma, dielectric lined waveguide dispersion equation. And the effects of the longitudinal magnetic field, plasma density and dielectric parameters on the linear spatial growth rate and the energy ratio are presented.

Analytical theory of wave propagation along a corrugated waveguide filled with plasmas immersed in a finite axial magnetic field is presented in this paper. Preliminary numerical calculations are also done, showing that the intensity of magnetic field has considerable influence on the dispersive characteristics of wave propagation and the properties of such devices.

In a relativistic electron cyclotron maser with an axisymmetrical quasioptical cavity of oblique rotation at arbitrary angle, the rotating angle has a great influence on beam-wave interaction. Two different physical mechanisms are found with the rotating angle ranging from 0° to 90°. One is cyclotron auto-resonance maser regime for small angle, with small optimized external magnetic field; the other is electron cyclotron resonance maser regime for large angle, with comparatively large optimized magnetic field.

The phase and frequency locking of microwave, millimeter wave power combining were analysed and summarized in an all-round way. The master/slave phase locking of cavity oscillators, the peer phase locking of mutually coupled oscillators, and the peer phase locking of ring-connected multiple oscillators were investigated. The results of numerical calculations, and the relations of phase to phase locking model and oscillator parameters were given. And the cavity and space power combining aspects for microwave and millimeter wave were presented.

Self consistent nonlinear theory is applied to analyze the large orbit magnetron-type gyrotron in detail; many calculations are carried under different cavity dimensions and electron beam parameters. The influence of electron beam thickness and output structure is taken into consideration. Dimensions of a 16 slot, 35 GHz, 8th harmonic tube are given. >

The angular spectrum of spontaneous emission in a two-dimensional undulator free-electron laser is analyzed theoretically. Numerical calculation shows that thes-th harmonic spontaneous emission power density can be greatly enhanced by using a two-dimensional undulator, for whichl=s, so the harmonic number can be selected by selectingl. Therefore, the higher harmonic operation of a free-electron laser can be realized selectively.

Based on the Fabary-Parot cavity and subwavelength holes array, a 3-mirror quasi-optical cavity is presented and explored. The electron beam-wave interaction in this cavity is proposed and the results show that this interaction can reach an attractive value with reasonable current density of electron beam at THz regime.

The mechanism of this novel 3D diffraction radiation phenomenon is revealed. A rigorous theoretical solution is obtained for the problem of electromagnetic diffraction radiation of sub-wavelength holes array (SHA) excited by a point charge moving parallel to the one surface of SHA.

Mimicking surface plasmons can be used to interact with two-electron beam to generate THz radiation. And the 3-mirror quasi-optical cavity has high Q and can collect the radiation energy efficiently, so the interaction in such special cavity may be a good way to generate THz.

The experiment of a Ka-band folded waveguide extended interaction oscillator (FWEIO) tube, consisting of 21-gap resonator, is reported in this paper. In the FWEIO experiment, the tube generates about 330W output power at 35.5GHz with the bandwidth 180MHz, the interaction efficiency of 23%.