A supplemental device to return escaping particles to a magnetic mirror reactor

Mitsuaki Nagata,Keiichi Sawada

doi:10.1140/epjti/s40485-018-0042-4

Abstract

Cyclotron resonance is now applied as one of the important means for heating plasma in a fusion reactor. We examined this phenomenon from the viewpoint of electron gyration orbits through a solution of the linearized relativistic equation of motion. We found a powerful term that accelerates a relativistic charged particle largely at a resonance point when a magnetic field strength is very large. In this study, aiming an effect of this term, we consider applying a resonance phenomenon to reducing the number of charged particles that escape from a magnetic mirror reactor. We install a long supplemental device at the exit of a main magnetic bottle and make a cyclotron resonance space within the device, as shown in Fig. 7. If velocities (perpendicular to a magnetic field) of charged particles are accelerated largely within the cyclotron resonance space, the reflection efficiency of a magnetic mirror behind the resonance space ought to be improved. Based on this idea, we discuss such a supplemental device for recovering the maximum number of escaping charged particles.

Highlights

In the early days of cyclotrons, the study of cyclotron resonance served to determine gas plasma condition from the characteristics of electromagnetic waves having passed through the plasma
We examined cyclotron resonance from a viewpoint of gyration orbits of an electron in a plane perpendicular to a static magnetic field, using a solution of the linearized relativistic equation of motion which was obtained under the condition given in Eq (5) later
We found a term that accelerates a relativistic charged particle rapidly, when a magnetic field strength is very large, at a resonance point where an electric field frequency is equal to a charged particle’s cyclotron frequency

Summary

Introduction

In the early days of cyclotrons, the study of cyclotron resonance served to determine gas plasma condition from the characteristics of electromagnetic waves having passed through the plasma [1] But large quantities of wave energy are absorbed by charged particles when the wave frequency is nearly equal to the particles’ cyclotron frequency. (12), (20) and (21), the second part works clearly to increase a velocity-magnitude (perpendicular to a magnetic field) of a relativistic electron, when ωct ≫ 1.

Results

Conclusion