Michael V. Fazio

Bio: Michael V. Fazio is an academic researcher from SLAC National Accelerator Laboratory. The author has contributed to research in topics: Klystron & Amplifier. The author has an hindex of 10, co-authored 58 publications receiving 360 citations. Previous affiliations of Michael V. Fazio include Stanford University & Los Alamos National Laboratory.

Ultracompact pulsed power

Abstract: Now more than ever, the pulsed power field is driven by size, weight, and volume constraints. In both the military and commercial arenas, there is an overwhelming need to provide more and more capability in ever smaller and lighter packages. The need for higher energy density, power density, reliability, and efficiency is driving progress in the field. This paper provides a review of the state of the art in various types of pulsed power components such as solid-state switches, capacitors, and power sources. In some cases, familiar components such as switch tubes are being replaced with whole new classes of devices. Batteries are being replaced by hydrocarbon or hydrogen-fueled mechanical systems that alter our paradigm for prime power sources. Trends over the past few years and future possibilities for ultracompact systems are discussed, including advanced techniques for heat removal and energy recovery. Finally, a few practical examples of ultracompact systems are given, emphasizing peak power and peak power density.

Advances in virtual cathode microwave sources

Abstract: The evolution of the virtual cathode microwave source and its current performance are described. Explosive generator driven virtual cathode oscillators, resonant cavity sources, and phase-locking and amplifier sources are covered. Areas for future development are discussed. >

Developing Sheet Beam Klystron Simulation Capability in AJDISK

Abstract: AJDISK is a 1-D large signal klystron simulator developed at Stanford Linear Accelerator Center. A brief discussion of AJDISK's simulation algorithm is given and fully developed to show how AJDISK was extended to enable sheet beam klystron simulations. The primary requirement for extending disk simulators to sheet beam simulators is a space charge equation. Therefore, the electric field due to an infinitely thin plate of charge (infinitely thin in the direction of propagation) in a rectangular drift tube is derived. The derivation is extended to a 2-D space charge equation in which the plate is split into a series of rods with varying positions in $y$ . The derived equations are compared with the numerical simulations and measurement.

Narrow‐band microwave generation from an oscillating virtual cathode in a resonant cavity

Abstract: An experimental approach using a high Q, resonant cavity surrounding an oscillating virtual cathode has achieved frequency stabilization, and repeatable narrow‐band operation of the virtual cathode microwave source. A cylindrical cavity resonator is used with the microwave power being extracted radially through circumferential slot apertures into dominant‐mode L‐band waveguide. The electron‐beam/cavity interaction produces strong feedback between the induced cavity field and the oscillating virtual cathode, forcing it to lock to the resonant frequency of a cavity mode over a large variation in electron beam current. The 3‐dB frequency bandwidth observed during single 100‐ns pulses is less than 1%. The 3‐dB bandwidth appears to be limited by the finite temporal width of the microwave pulse.

Intense space-charge beam physics relevant to relativistic klystron amplifiers

Abstract: In this paper, we examine intense space-charge beam physics that is relevant to beam bunching and extraction in a mildly relativistic klystron amplifier, and give numerical examples for a 5 kA, 500 keV electron beam in a 1.3 GHz structure. Much of the peculiar beam physics in these types of devices results from the partitioning of beam energy into kinetic and potential parts. Both tenuous-nonrelativistic and intense-relativistic beams produce effects different in nature from those produced by intense, mildly relativistic beams because the potential energy requirements are either negligible or fixed. In particular, we demonstrate anomalous beam bunching aided by the nonlinear potential requirements and we discuss maximum power extraction as a function of beam bunching. We show that although the space-charge effects can produce quite high harmonic current content, the maximum power extraction from the beam into RF typically occurs at relatively modest bunching. >

Review of high-power microwave source research

Abstract: This article reviews the state-of-the-art in high-power microwave source research. It begins with a discussion of the concepts involved in coherent microwave generation. The main varieties of microwave tubes are classified into three groups, according to the fundamental radiation mechanism involved: Cherenkov, transition, or bremsstrahlung radiation. This is followed by a brief discussion of some of the technical fundamentals of high-power microwave sources, including power supplies and electron guns. Finally, the history and recent developments of both high-peak power and high-average power sources are reviewed in the context of four main areas of application: (1) plasma resonance heating and current drive; (2) rf acceleration of charged particles; (3) radar and communications systems; and (4) high-peak power sources for weapons-effect simulation and exploratory development.

Quantum Sensing with Squeezed Light

Abstract: The minimum resolvable signal in sensing and metrology platforms that rely on optical readout fields is increasingly constrained by the standard quantum limit, which is determined by the sum of pho...

Evolution of pulse shortening research in narrow band, high power microwave sources

Abstract: The achievements resulting from the application of advanced pulsed power to the generation of high power microwaves (HPM) have included the generation of multi-gigawatt pulses of RF energy. The power achievable is orders of magnitude greater than conventional microwave sources can generate. However, the introduction of the HPM technology into logical applications has been limited to date due to the phenomenon of pulse shortening in which the RF pulse terminates before the pulse power source used to produce it. Conventional microwave tubes can generate a few to 10 MW of power with pulsewidths of many microseconds when required. High power microwave sources can produce gigawatts of power, but only for relatively short pulsewidths, typically tens to hundreds of nanoseconds. An international effort during the past few years has generated important new discoveries toward the elimination of pulse shortening. Some of the new techniques have the potential for helping the conventional tube industry as well as being practical for high power microwave sources. This paper reviews the pulse shortening problem, its causes, and the worldwide scope and direction of research conducted to date to resolve it. The paper also discusses the potential remedies for the problem and recommends a course of research to further progress on the issue.