Effects of perturbing B-field orientation on magnetic priming of a Relativistic Magnetron

• Published in: 2008 IEEE International Vacuum Electronics Conference pp. 270 - 271
• Main Authors: Hoff, B.W., Gilgenbach, R.M., Jordan, N.M., Lau, Y.Y., Cruz, E., French, D., Gomez, M.R., Zier, J.C., Spencer, T.A., Price, D.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01-05-2008
• Subjects: Anodes; Cathodes; Laboratories; Magnetic fields; Magnetostatics; Microwave ovens; Permanent magnets; Saturation magnetization; Testing; Wires
• ISBN: 1424417155; 9781424417155
• DOI: 10.1109/IVELEC.2008.4556506

Experiments have been performed testing magnetic priming at the cathode of a relativistic magnetron to study the effects on high power microwave performance. Magnetic perturbations were imposed utilizing three, high-permeability nickel-iron wires embedded beneath the emission region of a 1.27 cm diameter cathode, spaced 120 degrees apart (for N/2 symmetry in an N (6) cavity magnetron). These three, high-permeability wires perturb both the axial and radial magnetic fields near the emission region of the cathode. Magnetic priming was demonstrated at UM to increase the percentage of p-mode shots by 15% over the baseline case in the relativistic magnetron. Improvements in microwave power, pulse width and start-oscillation time were also observed. Earlier experimental research by Neculaes and recent simulation work suggest that using permanent magnets with radially-directed remanence fields centered under the cathode emission region instead of high permeability wires can yield improved magnetron performance.