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AND VACUUM DISCHARGES

Influence of the Pulsating Electric Field on the ECR Heating in a Nonuniform Magnetic Field A. A. Balmashnov and A. M. Umnov People’s Friendship University of Russia, ul. MikluhoMaklaya 6, Moscow, 117198 Russia email: [email protected] Received September 14, 2010

Abstract—According to a computer simulation, the randomized pulsating electric field can strongly influ ence the ECR plasma heating in a nonuniform magnetic field. It has been found out that the electron energy spectrum is shifted to the high energy region. The obtained effect is intended to be used in the ECR sources for effective Xray generation. DOI: 10.1134/S1063780X11060031

INTRODUCTION A study of the possibility for increasing the plasma electrons heating effectiveness at the electron cyclo tron resonance (ECR) is of great scientific and practi cal interest. Specifically, it is important for creation of the ECR sources of Xrays [1–3]. Their compactness and energy effectiveness, and also absence of a high accelerating potential determine the availability of their application. It is well known that the dominant factor limiting the electron energy at the ECR heating is cycling a phase of interaction of electrons with the microwave electric field due to the relativistic effect. As a result, pulsations of electron energy are obtained. It happens even at the absence of stochastic failure of an interac tion phase, which is produced by any random process. This relativistic effect determines an electron distribu tion function where the essential part of electrons is situated at the lowenergy region. Compensation of the relativistic effect associated with an electron mass change can be made by spatial structurization of a magnetic field [4] or by variation of its value in the course of operation [5]. Stochastic processes at the ECR interaction can limit the electron energy growth or favor its increase. In rarefied plasma, where collision losses of electron energy can be neglected, the influence of stochastic phenomena appears in the change of a phase of inter action of an electron with a microwave field. In real conditions, the failure of an interaction phase can arise due to particle collisions as well as due to interac tion of electrons with fluctuating plasma fields [6, 7]. Also, in practice, a stochastic process may be realized by phase chaotization of the initial pumping wave, by application of waveguide systems with simultaneously excited different modes of oscillations [8], and also by external pulsating electric and (or) magnetic fields. As

a result of the fields action at synchronization of pul sations with the frequency of an electron energy varia tion according to a relativistic effect, we can expect the particle energy growth under certain conditions; at random pulsations we can expect, as the main effect, evolution of electron distribution function—deple tion of its lowenergy region and transition of the par ticles in great numbers into the highenergy region. Our longrange goal is to study the in