Ultra-High-Efficiency Relativistic Magnetron and Improved MILO Capabilities
Abstract
The relativistic magnetron is the most compact and efficient high power microwave source. The University of New Mexico (UNM) has been studying relativistic magnetrons for over 15 years. Our initial contribution was the invention of the ~transparent cathode~ (TC) that increased magnetron beam-to-microwave conversion efficiency and decreased the time-for-start of oscillations. Next, we showed that a TC in a magnetron with diffraction output (MDO) can achieve 70% beam-to-microwave efficiency, provided that axial loss current can be suppressed. We demonstrated how the use of endcaps on a TC can greatly diminish axial loss current. We then proposed a permanent magnet solution to a compact MDO where, for the price of decreased efficiency, a very compact HPM source without the bulky extraction section can be realized. We next proposed a relativistic MDO without a physical cathode where a virtual cathode forms in the interaction region to power the MDO with efficiency comparable to that of an MDO with a TC. Most recently we proposed a magnetic mirror field for an MDO that can completely eliminate axial loss current. This half-cusp-like magnetic field configuration replaces the downstream virtual cathode that was described in our earlier work and demonstrates >90% efficiency in simulations. We believe that this MDO with virtual cathode and magnetic mirror will not suffer from pulse shortening since there is no physical cathode electrode in the interaction space for impedance collapse to take place. Hence, we believe this configuration can operate at exceptionally long pulse lengths. This unique device will also be studied for multi-tone and continuous tuning capabilities.UNM has also been developing a MILO over the past few years to study plasma formation and evolution in the device and mitigating such plasmas to achieve higher efficiency operation. Here we propose to study in simulation and experiment strategies for achieving higher efficiency MILO operation and multi-tone capabilities.UNM will also be advancing pulsed power drivers for MDOs and MILOs using a fast, high energy Marx generator and a linear transformer driver.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 23, 2019
- Source ID
- N000141912155
Entities
People
- Edl Schamiloglu
Organizations
- Office of Naval Research
- United States Navy
- University of New Mexico