A pulse-periodic gyroresonant plasma accelerator

A plasma electron accelerator based on the gyromagnetic autoresonance effect is described. Elec-trons of the initially cold internal-injection plasma (a classical ECR discharge) are accelerated in the mag-netic field of a magnetic mirror trap under a one-stage effect of the resonant microwave field and an addi-tional pulsed magnetic field. The synchronism in maintaining the resonance conditions is ensured by a smooth increase in the pulsed magnetic field in the course of a microwave pulse. At the moderate values of the input microwave power (up to 2.5 kW) and the steady-state and pulsed magnetic fields (each up to 1 kG), it is possible to obtain stable relativistic plasma bunches, in which the energy of the electron components is a few hundred keV. The measured X-ray bremsstrahlung spectra have features characteristic of the energy dis-tribution of photons, and the high-energy tails are recorded in the region of 600-800 keV. The dependences of the bremsstrahlung characteristics on the experimental conditions-the value of the steady-state magnetic field and the amplitude of the pulsed magnetic field-are investigated. The experimental data are in good agreement in the quantitative sense with the results of the computer simulation and with the earlier studies. © Pleiades Publishing, Ltd., 2012.