Fine structure of the emission spectra of a relativistic Cherenkov plasma maser

On the theory of a Cherenkov relativistic plasma emitter with a coaxial electrodynamic system

“…In such a waveguide, efficient Cherenkov excitation and emis sion of an E type nonpotential plasma wave occur. Subsequent numerous successful experimental inves tigations [10][11][12] completely confirmed the theory: high power relativistic Cherenkov plasma microwave amplifiers and generators based on a cable plasma wave were created [13,14].…”

“…We give the two limiting expressions for δ from Eqs. (13): first, for a low current beam with the cur rent much lower than the vacuum current, and, sec ond, for the beam current higher than the limiting vac uum current but lower than the Pierce limiting cur rent. In the first case of the low current beam, where…”

“…As decreases, the sin gle particle Cherenkov resonance frequency decreases and vanishes at (19) The intersection of the curve given by Eq. (13) for the slow wave of the beam and the dis Fig. 1 is the point of the collective Cherenkov resonance (wave-wave resonance).…”

“…We note that the solutions of general transcendent dispersion rela tion (22) have not yet been reported; only solutions of simplified (truncated) equation (27) were discussed [7,20]. We consider only the azimuthally symmetric case l = 0 and take the following parameters of the sys tem that are close to those used in real experiments [10][11][12][13][14]: 1 cm, Δ b = 0.1 cm, and cm/s (γ = 2). 2 In this case, the limiting vacuum current of the beam is kA.…”

“…(11) has the form (12) and the frequency spectra of the beam waves in the long wavelength limit are as follows: (13) Here, the signs + and -correspond to the fast and slow waves, respectively; and (14) It can be shown [19] that the parameter is propor tional to the ratio of the beam current to the Pierce limiting current. Formulas (13) are obtained under the assumption that the beam current is much lower than the Pierce limiting current [17,19], i.e., . We give the two limiting expressions for δ from Eqs.…”