Related papers: The effect of the electron-beam parameter spread o…
We simulated an axial vircator with a three-cavity resonator and expected generation efficiency 6-7 percents. For adequate description of physical processes taking place inside a vircator we used two independent PIC codes: self-developed…
Triode reflex geometry vircator operating within 3.0 - 4.2 GHz range with efficiency up to 6% is developed and experimentally investigated. Shiftable reflectors are shown to enable frequency tuning and output power control. Radiation…
The radiation instability in a split-cavity asymmetric resonator is considered for the relativistic case. The space charge of an electron beam is taken into account. In the small-signal approximation, the energy loss by particles passing…
The effect of an external harmonic signal on the characteristics of microwave generation in a nonrelativistic electron beam with virtual cathode (VC) formed in a static retarding electric field (low-voltage vircator system) has been…
Energy efficiency in terahertz range is evaluated experimentally of a spin-injection oscillator based on a ferromagnetic rod-film structure with point contact between the components. Choice of the film material influences substantially the…
The radiative instability of the relativistic electron beam in a periodic dielectric-filled cylindrical waveguide is considered. The dependence of the beam instability increment on the radiated wave frequency near the region of dispersion…
The energy-spread of the triple-pulse electron beam generated by the Dragon-II linear induction accelerator is measured using the method of energy dispersion in the magnetic field. A sector magnet is applied for energy analyzing of the…
The microwave resonator is one of the key components in the modern Electron Paramagnetic Resonance (EPR) spectroscopy setup, as it largely determines the performance characteristics and limitations of the entire spectrometer. In this…
Vircators (Virtual Cathode Oscillators) are sources of short-pulsed, high power, microwave (GHz) radiation. An essentially dimensional argument relates their radiated power, pulse energy and oscillation frequency to their driving voltage…
We experimentally demonstrate a Purcell effect-based design technique for improved impedance matching, and thus enhanced radiation efficiency from a small microwave emitter. Using an iterative process centred on comparing the phase of the…
This work presents an experimental protocol conceived to determine the vibrational distribution of barium monofluoride molecules seeded in a supersonic beam of argon. Here, as in many cases, the detection signal is related to the number of…
We investigate the effect of axial compression on the optimal design of columns, for the maximization of the fundamental vibration frequency. The compression may be due to a force at the columns' tip or to a load distributed along its axis,…
To make full use of photocathode material and improve its quantum efficiency lifetime, it can be necessary to operate laser away from the cathode center in photoinjectors. In RF guns, the off-axis emitted beam will see a time-dependent RF…
The problem of electromagnetic emission generation in plasma with electron beams is relevant both for practical applications and for interpretation of radio emission processes in astrophysical systems. In this work, we consider the case of…
This paper discusses the geometrical features and wideband performance of the beam with maximal ratio combining coefficients for a generic multi-antenna receiver. In particular, in case the channel is a linear combination of plane waves, we…
The generation of optical pulses at ultra low bias level, thus low energy cost, is explored in a commercial microcavity semiconductor laser in view of testing the principle of energy efficient information encoding in potential integrated…
This paper presents radiation efficiency and gain bounds for microstrip patch antennas. The presented bounds are shown to be good predictors of antenna performance. Using the bounds, patch miniaturization techniques based on high…
Third-harmonic generation can be realized via both $\chi^{(3)}$ and cascaded $\chi^{(2)}$ nonlinear processes in a triply-resonant microcavity. It is still unknown how these processes interfere with each other and the optimization of the…
We present a new kind of generator of internal waves which has been designed for three purposes. First, the oscillating boundary conditions force the fluid particles to travel in the preferred direction of the wave ray, hence reducing the…
We present a comprehensive analysis of coherence properties of the radiation from X-ray free electron laser (XFEL). We consider practically important case when XFEL is optimized for maximum gain. Such an optimization allows to reduce…