Electron Acceleration by Oscillating Electric Field

A unique experimental system with collisionless electrons has been developed to investigate waveparticle interaction and/or particle acceleration in turbulence. In the system, electrons are injected from a tip of electron source along a magnetic field in a region between two electrostatic potentials. Some of the electrons trapped in the potentials are accelerated and other electrons are decelerated by oscillating electric field localized at the electrostatic potential with larger magnitude. The accelerated electrons were observed as a current into a disk electrode placed outside the steady electrostatic potential with lower magnitude. The results show that the escaping electrons’ current was the superposition of (1) current enhanced at some discrete frequencies of the oscillating electric field and (2) current continuously increased with increasing the frequency of the oscillating electric field.