Two-Channel Generator of the 8-mm Wavelength Range for Radiation with Subgigawatt Power Level Pulses

On the radiation phase stability of a relativistic coaxial backward-wave oscillator at decimeter wavelengths

“…Stability of the radiation phase was also observed in the RBWO experiments at frequencies of 10 [2, 3] and 37 GHz [4,5]. Special devices were used in these experiments in obtaining a sharper front of voltage pulse in order to satisfy the theoretical condition of phase stabilization [5,6] (1)where T is the period of high frequency oscillations and C = [eI 0 Z/(2mc 2 )] 1/3 is the generalized Pierce parameter. In the latter formula, I 0 is the amplitude of an electron beam current; Z is its connective resistance with synchronous harmonics of the operating wave; e and m are the electron charge and mass, respectively; and γ 0 is the relativistic factor relating to diode voltage amplitude U 0 .…”

“…In the latter formula, I 0 is the amplitude of an electron beam current; Z is its connective resistance with synchronous harmonics of the operating wave; e and m are the electron charge and mass, respectively; and γ 0 is the relativistic factor relating to diode voltage amplitude U 0 . Temporal factor T U is determined through the maximal derivative at the front of the volt age pulse and its amplitude,When condition (1) is satisfied, the growth duration of the beam current determined analogously to (2) cer tainly has a lesser magnitude [5]. The spectral compo nents from the front of a current then have weakly vari able phases in the frequency band of interaction [6].…”

“…With allowance for possible frequency deviation δω (ω is the carrying frequency) during time τ m from pulse to pulse, it is necessary to satisfy the con ditions (3) where δϕ in is the initial phase instability [5]. Due to the relativistic energy dependence of the electron velocity at small variations of the amplitude of pulse voltage (δU 0 /U 0 < 1%), conditions (3) can be fulfilled if the shape of the pulse is reproduced quite stable.In contrast to [1][2][3][4][5], the main aim of this work is to verify the possibility of the phase stabilization of microwave radiation in experiments with a generator frequency of 1-2 GHz and pulse duration τ m = 100T and without making the voltage impulse front sharper. In a frequency range of 1-2 GHz, it is worthwhile to use the RBWO construction based on a coaxial delay system (CRBWO) [7].…”

Control of the Operation Mode of a Relativistic <italic>Ka</italic>-Band Backward-Wave Oscillator

“…Measurements of the MICD impedance, performed with a technique described elsewhere [41] [Fig. 3(a)], and the beam current waveforms recorded with the use of a collector pickup [42], connected instead of the SWS, have shown that the current pulse leading edge and the voltage pulse applied to the cathode are substantially different in waveform because of the nonlinear dynamics of explosive electron emission [43]. This is a typical situation where the accelerating voltage pulse sharpened with an NLTL has no prepulse during which conditions would arise for the transition of field emission to explosive electron emission [44].…”

Summation of emission from superradiant sources as a way to obtain extreme power density microwaves

“…The initiation is described of the generation of superradiant pulses [1-3] by emission from the leading edge of the electron bunch. In combination with the proven experimentally picosecond stability of explosive emission from a cold cathode [4], it provides the possibility for strong correlation of phase of the SR pulses with respect to the leading edge of the electron pulse [5].…”