High Power, High Frequency, Repetitively Pulsed Oscillators
Abstract
This proposal describes a research program to generate repetitive, high frequency, high power pulses from a Magnetically Insulated Line Oscillator (MILO). The MILO is a crossed-field high power microwave device which generates its own insulating magnetic field, thereby eliminating the need for external magnets. This feature can provide an overall improvement in system size, weight, and/or efficiency. MILOs were researched extensively in the 1990s in the US, and have received considerable attention internationally in recent years, particularly in China. Limited research has been conducted, particularly within the US, on high frequency (10+ GHz) MILOs. A push to higher frequency sources is necessary to maintain the effectiveness of our directed energy portfolio.Previous ONR research at the University of Michigan (UM) demonstrated both the viability of driving a MILO with a Linear Transformer Driver (LTD), and a multi-frequency harmonic MILO with reduced current requirements. Additionally, a novel Brillouin flow theory was developed which establishes MILO operation and insulation requirements, guiding the design process. Extending these efforts, UM proposes to develop an X-band (8-12 GHz) MILO driven by a 1.6-kJ Marx generator capable of producing highly-repeatable 20-400 kV, 100-200 ns voltagepulses at repetition rates of 1 Hz (10 Hz in burst fire operation). This Marx generator, funded by an ONR DURIP, will be deliveredto UM in fall of 2022.Using this system, UM will fabricate X-band MILOs using a variety of construction techniques and use these prototypes to investigate the dynamics of HPM repeatability, identifying and addressing sources of pulse-to-pulse variation in key metrics such as power, frequency, and phase. UM will continue the development of the BLUE LTD system, a 4-cavity system which can provide 100-400 kV pulses with a driver impedance of 0.5-20 #. When fully assembled and tested, BLUE will provide a platform for high power MILO experiments.To continue our work improving fundamental understanding of MILO operation, UM will analyze the treatment of Brillouin flow in the limits of a variable planar gap, a condition found in nearly all pulsed power devices. While the experimental work here focuses on X-band, we will also conduct an analytic and computational analysis of HPM sources for operation at even higherfrequencies, testing the limits of MILO frequency scaling.In collaboration with AFRL, UM will also test the MADCAP recirculating planar magnetron. This compact HPM source was designed and constructed, but not fully tested. Consequently, these experiments will provide the Department of Defense with valuable data on its performance.Approved for Public Release
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 12, 2023
- Source ID
- N000142312143
Entities
People
- Nicholas Jordan
Organizations
- Board of Regents of the University of Michigan
- Office of Naval Research
- United States Navy