Ion Diode Research on the Aurora Accelerator.
Abstract
Within the last few years interest in ion beams for inertial confinement fusion (ICF) applications has increased significantly. The Naval Research Laboratory (NRL), with support from JAYCOR, has been in the forefront of that research effort. The ion source which NRL has concentrated on is known as the pinch reflex diode (PRD). This type of ion diode was originated at NRL with JAYCOR assistance and is presently one of the few designs with application to ICF. The PRD, is comprised of a hollow cylindrical cathode of radius R separated from a plasma anode by a diode gap D. When a voltage is placed across the gap, electrons emitted from the cathode are accelerated toward the anode while being pinched toward the axis by their own magnetic field. The anode is normally made of a disk of thin dielectric material connected to a conducting backplate by a small conducting cylinder on axis. Electrons hitting the anode pass through and are reflexed back into the diode gap by the magnetic field from the current driven in the central button. Electrons undergo the combined reflexing and pinching motion until they are collected by the central button. Ions from the plasma formed on the front surface of the dielectric anode due to electron heating or flashover mechanisms are accelerated across the diode gap toward the cathode. The relative ion and electron current densities depend on the difference in crossing times of the two charge species. For diode voltages in the 1-10 MV range the ions move in nearly straight line trajectories at nonrelativistic velocities while the electrons are quickly accelerated to near the speed of light.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 27, 1982
- Accession Number
- ADA111663
Entities
People
- Robert A. Meger