By Kim Roth
Associate Professor Ryan McBride has received a 2018 Young Investigator Award from the Office of Naval Research. The three-year award grants $170,000 annually for McBride’s proposal, “High-Power Microwave Generation by Compact Linear Transformer Driver Technology.”
Generating high-power microwaves for directed energy from compact and efficient generators is crucial to a wide range of defense applications, and linear transformer driver (LTD) technology has the potential to drive some of the most compact, moderate-voltage, gigawatt-class high-power microwave (HPM) sources yet developed.
Linear transformer driver systems are well suited to drive particular types of HPM sources for several reasons, including their tunability, minimal stray high-voltage fields and electrical interference, and their capacity to be pulsed at high repetition rates, which increases the average output power of the HPM sources being driven.
But driving HPM sources with LTDs is not without its challenges. For example, the LTD must have an electrical impedance that is well matched to the electrical impedance of the HPM source. Since plasmas — electrically-charged gases — are involved, HPM impedance cannot be known until experimental testing begins. The LTD will need to be reconfigured multiple times to find the correct driver impedance.
Other challenges include controlling the plasmas in the HPM sources, which can affect the microwave-generating efficiency of the HPM source. These are some of the issues McBride and collaborators, including Dr. Nicholas Jordan, Professor Y.Y. Lau and Professor Ronald Gilgenbach, will address during the project.
“We’ve amassed a great team,” said McBride. “Since Professor Gilgenbach founded the lab some 38 years ago, Professor Y.Y. Lau has developed a wealth of plasma theory, enabling U-M to become a leader in HPM science and technology and training students in HPM.” U-M researchers were also part of an international collaboration to bring LTD technology to the United States in the late 2000s.
In addition to McBride’s Young Investigator Award, he was also part of the team that received the prestigious Defense Programs Awards of Excellence from the National Nuclear Security Administration. The award was bestowed for his role on the “Z-Machine Circuit Model Development Team.”