Production of relativistic, rotating electron beams by gyroresonant rf acceleration in a TE111 cavity

Abstract

The rf acceleration of moderate current (≲1 A) electron beams to 500 keV in a TE111 cylindrical cavity resonator is described. Experimental results are compared with theory. rf to beam energy conversion efficiencies in excess of 50% have been observed. The resultant axis-encircling beam with a large ratio of perpendicular velocity to longitudinal velocity is ideal as a driver for a high-harmonic gyrotron.

Theoretical and Experimental Investigation of Electron Beam Acceleration and Sub-Millimeter Wave Generation

“…The number of sections is chosen to yield the desired gain. For the 53() k\W TE• 21 (2) gyro-TWT described in Table 1. the spatial power profile an(d frequency bandwidth obtained from nonlinear, self-consistent simulations are shown in Figs.…”

“…The high frequency potential of this device is primarily limited only by the availability of high power, high frequency sources to drive the accelerator/buncher cavity (2]. For example, a tenth-harmonic gyro-multiplier utilizing a 140 GHz rf-accelerator would generate high power electromagnetic waves with a wavelength of 0.21 mm in a magnetic field of 50 kG.…”

“…If these two modes maser (CARM) [1] and the free electron laser (FEL) [2]. It are close in frequency, then strong parasitic intetcoupling can be obtained from corrugated waveguide as shown in Fig.…”

Experimental and theoretical investigation of high gradient acceleration

“…An intriguing feature of the CRL mechanism is autoresonance [33], [34], that is, the synchronism between the electrons and laser field is self-sustained in the course of acceleration in an ideal situation so long as the system is initially synchronized. Al--though recent proof-of-principle experiments [35]- [37] have successfully demonstrated the acceleration of electrons to moderately relativistic energies using microwaves and • the technique of tapering the guide field, there are severe limitations posed by laser field dispersion, synchrotron radiation losses, and the available strength of magnetic …”

Proposed research on advanced accelerator concepts

“…An intriguing feature of the CRL mechanism is autoresonance [27], [28], that is, the synchronism between the electrons and laser field is self-sustained in the course of acceleration in an ideal situation so long as the system is initially synchronized. Although recent proof-of-principle experiments [29]- [31] have successfully demonstrated the acceleration of electrons to moderately relativistic energies using microwaves and the technique of tapering the guide field, there are severe limitations posed by laser field dispersion, synchrotron radiation losses, and the available strength of magnetic field in laboratories.…”