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Thesis (M.S. in Physics)--Naval Postgraduate School, June 2009. / Thesis Advisor(s): Neighbours, John R. "June 1990." Second Reader: Buskirk, Fred R. Description based on title screen as viewed on 19 October 2009. DTIC Identifier(s): Electron accelerators, leakage (electrical), phermex acceleration, DCS (Digitizing Camera System), theses. Author(s) subject terms: Cherenkov radiation, transition radiations, EMP, radio frequency radiation, electron beam. Includes bibliographical references (p. 78-79). Also available in print.

M.Ing. (Electrical and Electronic Engineering) / This work reports on a study in the fields of "High power pulsed power supplies and electromagnetic pulse compression". A background discussion on the application of pulsed power on lasers is given. Pulse compression and high power pulsed power supply configuration is described. The work concentrates on simultaneous energy transfer electromagnetic pulse compression which is a technique used to achieve a saving of core material in a pulse compressor. An analytical expression for the saving was derived and verified experimentally. This result is applied in different pulse compressors designed for the pulsed power supplies of copper vapour lasers. The test results are provided and discussed. A windfall from the practical work is a design solution for the voltage sharing compensation network needed when switching semiconductors in series.

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M.Ing. / Pulse Compression is a technique that may be employed for the generation of extremely high amplitude current and voltage pulses. These pulses can be as short as 50 to 100 ns, and may have amplitudes in the kiloampere and kilovolt ranges. Pulse Compression entails the compression of relatively "flat" pulses in the time domain, to pulses of very high amplitudes and extremely short duration. The pulse amplitudes and durations necessary to be achieved in this research, lie in the range where the switching speeds and other parameters of semiconductors are inadequate and where even the working life of conventional gas discharge apparatus are drastically reduced by the extreme switching demands. The burden of excessively high current densities and unmanageable current rise-rates can be transferred from the semiconductor switches to electromagnetic switches, by making use of pulse compression. Pulse compression can be carried out simultaneously or separately for the compression of the current or voltage content of pulses derived from slowly switched sources, to obtain pulses of extremely short duration and very high amplitudes. The main theme of this dissertation is Current compression. Current compression is accomplished through series-resonance in capacitors and saturable inductors connected in a transmission-line configuration. Energy is transferred in this process from one stage to the next, with reduction in pulse-time in each successive stage and a commensurate increase in amplitude. The generated pulses can attain gigawatt amplitudes and nanosecond durations, whilst loading on the semiconducting switches remains low. In addition to design of the pulse-compressor proper, the work also includes design and development of a voltage-controlled pulse power supply, suitable for generating the initial pulses which are to be compressed. Multistage pulse compression is based on the non-linear characteristics of saturable inductors. Dynamic analogue-time simulation is indispensable in a study thereof, as new theory has to be validated and because non-linear analysis is complex and capable only of being executed by employing approximation methods. Because of the difficulties involved, a considerable amount of attention has been devoted to the development of suitable analogue-dynamic simulation programs for execution on a digital computer. A numerical technique has been developed to express non-linear parameters in differential form. This technique makes it possible to model and simulate virtually any non-linear, physically realizable lumped parameter system with ease. The program is based on State Space techniques and has been developed for its versatility, to accomplish the simulation of a wide variety of circuit configurations.

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ABSTRACT CLINICAL OUTCOMES INVOLVING THE USE OF EXTRACORPOREAL MAGNETIC INNERVATION IN THE TREATMENT OF URINARY INCONTINENCE by KATHY E. DAVIS Urinary incontinence affects approximately 25 million Americans, significantly diminishing their function and quality of life. It is estimated that 50% of all women will experience some form of urinary incontinence in their lifetime. Although women are disproportionately affected by urinary incontinence, 69% of men who have undergone prostatectomy also report post-surgical incontinence. Extracorporeal Magnetic Innervation (ExMI) is a novel conservative approach to the treatment of urinary incontinence. As a patient sits fully clothed on a chair, an electromagnet delivers a timed magnetic field that penetrates the pelvic floor, inducing a nerve impulse that prompts contractions of the muscles of the pelvic floor. When the magnet is switched off, the muscles relax. This forced, passive exercise of the pelvic floor muscles serves to build endurance and strengthen the muscles supporting the bladder during times of physical stress such as coughing, laughing or running. This study is a descriptive, retrospective analysis of data collected from a specialty continence center within a major Atlanta metropolitan outpatient facility. The records for all patients who received ExMI from 2000 to 2012 were reviewed. Of the 43 patients who had received ExMI, 35 met study inclusion criteria. Eight patients were eliminated from the study. Four of these patients experienced ExMI benefits for conditions unrelated to urinary incontinence and are discussed. Data were analyzed using descriptive and inferential statistics. . The majority of the patients were women (n=26, 74%); most patients had stress urinary incontinence (n=16, 46%) or mixed urinary incontinence (n=12, 34%). The patient outcome was determined by comparing the pad usage before treatment and at the end of treatment (16 weeks). The average number of pads used daily was significantly reduced to 1.6 3 + 0.94 (p<.0001). Treatment with ExMI for urinary incontinence was briefly popular in the United States shortly after it was introduced. Although ExMI is used extensively across Europe and Asia, very few studies on the efficacy of ExMI appear in the literature. These results will add to this body of knowledge.

From past experiments conducted with high intensity lasers, it has been known for some time that laser matter interactions result in the emission of short, transient electromagnetic pulses. Previous investigations into laser generated electromagnetic pulses provide basic information regarding frequencies where such pulses may be present, along with the time duration of the pulses. Such investigations have also demonstrated a number of measurement techniques in which basic information on the pulses may be obtained. The purpose of this current investigation is to obtain a more thorough description and understands of electromagnetic pulses generated for laser matter interaction. To this end, spatial radiation patterns emanating from various laser excited matter sources was predicted using antenna theory for far field radiators. Experimentally, it is the intention of this investigation to gather comprehensive time and frequency domain data on laser matter generated electromagnetic pulses using a number of specific laser targets. Radiation detection techniques using broadband, calibrated EMC horn antennas were devised. A unique measurement system known as an inverse superhetereodyne receiver was designed, tested and demonstrated. An experimental setup using such instrumentation was established. Using the above instrumentation and experimental setup should yield comprehensive time and frequency domain data over a spectra range of 1-40 GHz and with a time resolution of 50 ps. Because the experimental system employed is calibrated, measurements can be corresponded to incident electromagnetic fields. Several tests were conducted to ensure the proper operation of experimental apparatus. A modulation test was conducted on the inverse superhetereodyne receiver to ensure that the experimentally observed signals appeared when and where predicted within the receiver's bandwidth. The experimental setup was used to measure radiation emitted from an electrostatic discharge source of known distance and discharge voltage. Frequency domain data from the discharges were collected and compiled using a Matlab application ultimately intended to measure laser matter interaction generated electromagnetic pulses, resulting in a compiled frequency domain description comprising 1-17 GHz. The inverse Fourier transform was used to retrieve the time domain response from the compiled data. The discharge gaps characteristics where systematically altered as to allow a parametric study of the compiled data. The discharge measurements demonstrate the measurement system's ability to analyze unknown, short duration; broadband microwave signals.

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