Accession Number : AD0470633


Title :   THE EFFECT OF CROSSED MAGNETIC FIELD ON POTENTIAL MINIMUM STABILITY.


Descriptive Note : Research rept.,


Corporate Author : CALIFORNIA UNIV BERKELEY ELECTRONICS RESEARCH LAB


Personal Author(s) : Yuechungho,Raymondd


Report Date : 13 Jul 1965


Pagination or Media Count : 78


Abstract : Guns used to produce beams for crossed-field microwave amplifiers can be broadly divided into two categories: long and short. If the width of the cathode in the direction normal to the magnetic field is small is comparison with a cycloid length, the gun is called 'short'. Many practical guns, especially for high-power devices, have cathode widths which are comparable with, or even much larger than, a cycloid length. These 'long' guns have been found to produce a beam with much greater broadband noise when operated spacecharge limited. In this paper we wish to construct a simple space-charge feedback model for studying the noise phenomena in the space-charge-limited condition as a two-dimensional problem in a long gun as well as a short gun from the viewpoint of potential minimum instability. The noise analysis for the space-charge-limited ordinary diode is included to provide a simplified introduction. It indicates a space-charge smoothing of shot noise and we have used it as our limiting case, so as to check our model and calculations. A method for considering current sorting and beam-current perturbation in an M-type gun is discussed. A simple two-dimensional feedback model based on a set of fixed trajectories is presented. The calculations from this model show no instability of the potential minimum. Suggestions have been made for furthering this work to find a theoretical model which explains experimental results. (Author)


Descriptors :   ARMY RESEARCH , FEEDBACK , SPACE CHARGE , CROSSED FIELD DEVICES , ELECTRON BEAMS , CONFIGURATIONS


Distribution Statement : APPROVED FOR PUBLIC RELEASE