<title>Basic research in High-Power Microwaves (HPM): recent progress in university and Air Force Research Laboratory efforts</title>

Abstract

This paper describes progress in a cooperative research program of national scale that is focused on crucial research issues in the development of high energy microwave sources. These have many applications in the DOD and industry. The program includes participation by and cooperation among University, Industrial and Government research laboratories. The Air Force Office of Scientific Research (AFOSR), in cooperation with the Phillips Laboratory, the Naval Research Laboratory, and the Army Research Laboratory, established a tri-service research consortium in 1995 to investigate novel high energy microwave sources. The program is part of the DOD's Multidisciplinary University Research Initiative (MURI) and has been funded at a rate of $3.0M per year for up to five years. All research performed under this program is unclassified. Under its auspices, HPM scientists at nine US universities are pursuing twenty-two separate research projects under the leadership of Neville Luhmann at UC-Davis, Victor Granatstein at Maryland, Magne Kristiansen at Texas Tech, Edl Schamiloglu at New Mexico, John Nation at Cornell, Ned Birdsall at UC-Berkeley, George Caryotakis at Stanford, Ronald Gilgenbach at Michigan. and Anthony Lin at UCLA. To facilitate the rapid transition of research results into the industrial community, collaborative subcontracts are already in place with James Benford at Microwave Sciences, Carter Armstrong at Northrop, and Glen Huffman at Varian Associates. The program builds on over a decade of microwave research efforts funded by the plasma physics office at AFOSR It also is synergistic with the ongoing Tri-Service Vacuum Electronics Initiative led by Robert Parker of NRL as well as with the AFOSR's and Rome Laboratory's long-standing Advanced Thermionic Research Initiative (ATRI) An overview will be given of the broad spectrum of research encompassed by the university and Air Force Research Laboratory work. Areas of collaboration and technology transfer will be highlighted. The areas in which the three university consortia conduct research are described, and the connectivity to industry and to the DOD laboratories are discussed. There are a number of critical technical barriers to reaching the desired goals for high power and high energy sources. These are discussed and the planned focus and progress of research to resolve them is also presented. Some of the accomplishments to date will be discussed along with their significance. In particular, work on ultra-wide band breakdown and switching, flash-over of windows, pulse shortening in narrowband tubes, novel gyro devices, and plasma-RF interactions will be discussed.