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An Exploding Wire as a Fuse for the LASL Capacitor Bank--Zeus

Description: Abstract: "An exploding copper wire, one millimeter in diameter, 30 centimeters long, has been developed as a fuse component for a Los Alamos capacitor energy source to be employed in controlled thermonuclear research studies. The fuse allows the passage of the high normal duty "action" (13,700 ampere-coulombs per capacitor) at a 20-second repetition rate. However, it interrupts the circuit to a shorted capacitor in 12 microseconds, thereby protecting the faulted capacitor from explosive energy consumption. The initial phase of the development included observations of various metals (copper, silver, iron, and nickel) as well as various configurations (straight wires, helixes, foils, and tubes). Direct scaling of previous small exploding wire studies at Sandia Corporation was demonstrated with scaling factors up to 700,000."
Date: June 4, 1959
Creator: Cnare, Eugene C.
Partner: UNT Libraries Government Documents Department

Electron density and collision frequency studies using a resonant microwave cavity as a probe

Description: Electron densities and collision frequencies were obtained on a number of gases in a dc discharge at low pressures (0.70-2mm of Hg). These measurements were performed by microwave probing of a filament of the dc discharge placed coaxially in a resonant cavity operating in a TM010 mode. the equipment and techniques for making the microwave measurements employing the resonant cavity are described.
Date: May 1973
Creator: Freeman, Ronald Harold
Partner: UNT Libraries

Dynamics of electronegative plasmas for materials processing. Final report

Description: Purpose was to study equilibrium particle and energy balance and heating mechanisms in electronegative rf discharges. Attention is given to formation of non-Maxwellian electron distributions and their effect on macroscopic parameters. Research includes theory, particle- in-cell simulation, and experimental investigations. Sheath heating theory and simulation results for electropositive plasmas are used as guide. The investigation was centered on, but not limited to, study of oxygen feedstock gas in capacitively and inductively coupled rf discharges.
Date: December 31, 1996
Creator: Lichtenberg, A.J. & Lieberman, M.A.
Partner: UNT Libraries Government Documents Department

Initial Peak Surge Current Detection Circuits

Description: Test requirements for several components specifies that surge currents be monitored to determine if the initial peak surge current exceeds a certain predetermined amplitude. This report describes and evaluates two circuits which were developed by Organization 2451 to meet this requirement in production testing.
Date: February 1961
Creator: Conrad, Milo M.
Partner: UNT Libraries Government Documents Department

High altitude atmospheric discharges according to the runaway air breakdown mechanism

Description: High altitude optical transients - red sprites, blue jets, and elves - are modeled in the context of the relativistic electron runaway air breakdown mechanism. These emissions are usually associated with large mesoscale convective systems (hereafter MCS). In thunderstorms cloud electrification proceeds over a time scale long enough to permit the conducting atmosphere above the cloud to polarize and short out the thunderstorm electric field. When a lightning strike rapidly neutralizes a cloud charge layer runaway driving fields can develop in the stratosphere and mesosphere. According to present simulations of the full runaway process the variety of observed optical emissions are due to the nature of the normal lightning event in the MCS that kick starts the runaway avalanche. In this paper the authors describe some details of the model, present the results of the evolution of the primary electron population, and summarize the initial conditions necessary for different types of discharges. Two companion papers present (a) the predicted optical, gamma ray, and radio emissions caused by these electrical discharges, and (b) the time evolution of the secondary electron population and its implications in terms of observables.
Date: April 1, 1997
Creator: Symbalisty, E.; Roussel-Dupre, R.; Yukhimuk, V. & Taranenko, Y.
Partner: UNT Libraries Government Documents Department

Surface Dependent Electron and Negative Ion Density in Inductively Coupled Discharges

Description: Electron and negative ion density have been measured in a modfied Applied Materials DPS metal etch chamber using gas mixtures of BCl{sub 3}, Cl{sub 2} and Ar. Measurements were performed for four dflerent substrate types to examine the influence of surface material on the bulk plasma properties; aluminurq alumina, photoresist and 50 percent patterned aluminum / photoresist. Electron densities in the Cl{sub 2} / BCl{sub 3} mixtures varied from 0.25 to 4 x 10{sup 11} cm{sup -3}. Photodetachment measurements of the negative ion density indicate that the negative ion density was smaller than the electron density and that the electron to negative ion density ratio varied between 1 and 6. The presence of photoresist had a dominant intluence on the electron and negative ion density compared to alumina and aluminum surfaces. In most cases, the electron density above wafers covered with photoresist was a factor of two lower while the negative ion density was a factor of two higher than the aluminum or alumina surfaces.
Date: January 18, 1999
Creator: Blain, M.G.; Hamilton, T.W.; Hebner, G.A.; Jarecki, R.L. & Nichols, C.A.
Partner: UNT Libraries Government Documents Department

Assessment of the non-destructive nature of PASD on wire insulation integrity.

Description: The potential of a new cable diagnostic known as Pulse-Arrested Spark Discharge technique (PASD) is being studied. Previous reports have documented the capability of the technique to locate cable failures using a short high voltage pulse. This report will investigate the impact of PASD on the sample under test. In this report, two different energy deposition experiments are discussed. These experiments include the PASD pulse ({approx}6 mJ) and a high energy discharge ({approx}600 mJ) produced from a charged capacitor source. The high energy experiment is used to inflict detectable damage upon the insulators and to make comparisons with the effects of the low energy PASD pulse. Insulator breakdown voltage strength before and after application of the PASD pulse and high energy discharges are compared. Results indicate that the PASD technique does not appear to degrade the breakdown strength of the insulator or to produce visible damage. However, testing of the additional materials, including connector insulators, may be warranted to verify PASDs non-destructive nature across the full spectrum of insulators used in commercial aircraft wiring systems.
Date: September 1, 2003
Creator: Lockner, Thomas Ramsbeck; Peña, Gary Edward; Schneider, Larry X.; Higgins, Matthew B. & Glover, Steven Frank
Partner: UNT Libraries Government Documents Department

Observations and Modeling of Long Negative Laboratory Discharges: Identifying the Physics Important to an Electrical Spark in Air

Description: There are relatively few reports in the literature focusing on negative laboratory leaders. Most of the reports focus exclusively on the simpler positive laboratory leader that is more commonly encountered in high voltage engineering [Gorin et al., 1976; Les Renardieres Group, 1977; Gallimberti, 1979; Domens et al., 1994; Bazelyan and Raizer 1998]. The physics of the long, negative leader and its positive counterpart are similar; the two differ primarily in their extension mechanisms [Bazelyan and Raizer, 1998]. Long negative sparks extend primarily by an intermittent process termed a 'step' that requires the development of secondary leader channels separated in space from the primary leader channel. Long positive sparks typically extend continuously, although, under proper conditions, their extension can be temporarily halted and begun again, and this is sometimes viewed as a stepping process. However, it is emphasized that the nature of positive leader stepping is not like that of negative leader stepping. There are several key observational studies of the propagation of long, negative-polarity laboratory sparks in air that have aided in the understanding of the stepping mechanisms exhibited by such sparks [e.g., Gorin et al., 1976; Les Renardieres Group, 1981; Ortega et al., 1994; Reess et al., 1995; Bazelyan and Raizer, 1998; Gallimberti et al., 2002]. These reports are reviewed below in Section 2, with emphasis placed on the stepping mechanism (the space stem, pilot, and space leader). Then, in Section 3, reports pertaining to modeling of long negative leaders are summarized.
Date: December 13, 2011
Creator: Biagi, C J & Uman, M A
Partner: UNT Libraries Government Documents Department

THE THEORY AND DESIGN OF THE TRIGGERED SPARK GAP

Description: The basic theory of operation of the triggered spark gap is established, and qualitative and quantitative engineering design data are given. From the basic twoelectrode gap, a three-electrode or triggered gap model is established with its static and dynamic triggering characteristics shown. Several geometry conditions such as gap spacings trigger electrode hole sizes and insulator effects are discussed, showing their influence upon the triggering mechanism. A suggested trigger mechanism is given based on that proposed by Sletten and Lewis for the trigatron and modified to fit the present analysis. (auth)
Date: May 22, 1959
Creator: Williams, T.J.
Partner: UNT Libraries Government Documents Department

Dynamics of electronegative plasmas for materials processing. Final report

Description: The purpose of this project is to study the equilibrium particle and energy balance and the heating mechanisms in electronegative r.f. discharges. Particular attention is given to the formation of non-Maxwellian electron distributions and their effect on the macroscopic parameters. The research includes theory, particle-in-cell simulation, and experimental investigations. The sheath heating theory and the simulation results developed for electropositive plasmas are used to guide the investigations. The investigation was centered on, but is not limited to, the study of oxygen feedstock gas in capacitively and inductively coupled r.f. discharges. 15 refs.
Date: December 31, 1996
Creator: Lichtenberg, A.J. & Lieberman, M.A.
Partner: UNT Libraries Government Documents Department

Theory of edge plasma in a spheromak

Description: Properties of the edge plasma in the SSPX spheromak during the plasma formation and sustainment phases are discussed. For the breakdown and formation phase, the main emphasis is on the analysis of possible plasma contamination by impurities from the electrodes of the plasma gun (helicity injector). The issue of an azimuthally uniform breakdown initiation is also discussed. After the plasma settles down in the main vacuum chamber, one has to sustain the current between the electrodes, in order to continuously inject helicity. We discuss properties of the plasma on the field lines intersecting the electrodes. We conclude that the thermal balance of this plasma is maintained by Joule heating competing with parallel heat losses to the electrodes. The resulting plasma temperature is in the range of 15 - 30 eV. Under the expected operational conditions, the ``current`` velocity of the electrons is only slightly below their thermal velocity. Implications of this observation are briefly discussed.
Date: May 1, 1998
Creator: Hooper, E.B., LLNL
Partner: UNT Libraries Government Documents Department

New mechanism for lightning initiation

Description: This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). To distinguish radio-frequency (rf) signals generated by lightning from the electromagnetic pulse produced by a nuclear explosion, it is necessary to understand the fundamental nature of thunderstorm discharges. The recent debate surrounding the origin of transionospheric pulse pairs (TIPPs) detected by the BLACKBEARD experiment aboard the ALEXIS satellite illustrates this point. We have argued that TIPP events could originate from the upward propagating discharges recently identified by optical images taken from the ground, from airplanes, and from the space shuttle. In addition, the Gamma Ray Observatory (GRO) measurements of x-ray bursts originating from thunderstorms are almost certainly associated with these upward propagating discharges. When taken together, these three measurements point directly to the runaway electron mechanism as the source of the upward discharges. The primary goal of this research effort was to identify the specific role played by the runaway-air-breakdown mechanism in the general area of thunderstorm electricity and in so doing develop lightning models that predict the optical, rf, and x-ray emissions that are observable from space.
Date: October 1, 1996
Creator: Roussel-Dupre, R.; Buchwald, M. & Gurevich, A.
Partner: UNT Libraries Government Documents Department

Concrete decontamination by Electro-Hydraulic Scabbling (EHS). Topical report

Description: Electro-Hydraulic Scabbling (EHS) technology and equipment for decontaminating concrete structures from radionuclides, organic substances, and hazardous metals is being developed by Textron Systems Division (TSD). This wet scabbling technique involves the generation of powerful shock waves and intense cavitation by a strong pulsed electric discharge in a water layer at the concrete surface. The high pressure impulse results in stresses which crack and peel off a concrete layer of a controllable thickness. Scabbling produces contaminated debris of relatively small volume which can be easily removed, leaving clean bulk concrete. This new technology is being developed under Contract No. DE-AC21-93MC30164. The project objective is to develop and demonstrate a cost-efficient, rapid, controllable process to remove the surface layer of contaminated concrete while generating minimal secondary waste. The primary target of this program is uranium-contaminated concrete floors which constitute a substantial part of the contaminated area at DOE weapon facilities.
Date: March 30, 1996
Partner: UNT Libraries Government Documents Department

Final report pulsed plasma processing of effluent pollutants and hazardous chemicals

Description: The electrical discharge techniques, called non-thermal, utilize high voltage breakdown of gases using short pulses of one to a few hundred nanoseconds. These short pulses between metal electrodes generate energetic electrons without appreciable thermal heating of the gas. The energetic electrons collide with gas molecules to form radicals. The radicals then react with pollutants to form harmless compounds. Our non-thermal experimental device used a wire in a pipe geometry. The wire was driven by a 40 kilovolt pulse 100 nanoseconds long. Gas was circulated in a loop through the pipe geometry in a closed system. This system permitted the introduction of various gas combinations prior to testing. The recirculated gas was heated to determine the effect on the electrical discharge, and chemical reactions. Additives were introduced to improve the efficiency (defined as energy input per unit molecule destroyed). The efficient was found to be the most important parameter in that the experiments generally required high energy inputs. However, we were able to significantly improve the efficiency of NO removal by the addition of hydrocarbons, nitric oxide has been removed with an energy cost of 15 ev per NO molecule. We believe the hydrocarbon additive serves by recycling the hydroxyl radicals during the oxidation of NO. The implementation of this process will depend largely on how much additives, electrical power consumption, and final NO{sub x} concentration are acceptable for a particular application.
Date: August 18, 1994
Creator: Vogtlin, G.; Bardsley, N.; Penetrante, B. & Warman, H.
Partner: UNT Libraries Government Documents Department

Concrete decontamination by Electro-Hydraulic Scabbling (EHS)

Description: EHS is being developed for decontaminating concrete structures from radionuclides, organic substances, and hazardous metals. EHS involves the generation of powerful shock waves and intense cavitation by a strong pulsed electric discharge in a water layer at the concrete surface; high impulse pressure results in stresses which crack and peel off a concrete layer of controllable thickness. Scabbling produces contaminated debris of relatively small volume which can be easily removed, leaving clean bulk concrete. Objective of Phase I was to prove the technical feasibility of EH for controlled scabbling and decontamination of concrete. Phase I is complete.
Date: November 1, 1994
Partner: UNT Libraries Government Documents Department

Electrical discharge machining of type-N(f) microwave connectors

Description: A particular out-of-specification mechanical dimension on Type-N(f) [Type-N(female)] microwave connectors sometimes disqualifies otherwise perfectly acceptable microwave devices from being used in calibration systems. The Miniature Machining Group at Sandia National Laboratories applied a technique called Electrical Discharge Machining (EDM) to quickly and economically machine these devices without disassembly. In so doing, they facilitated the use of existing components without the need to purchase new devices. The technique also improves an uncertainty of calibration known as Mismatch Uncertainty by optimizing the reflection coefficient of the calibration test port. This effects a reduction in overall calibration uncertainties.
Date: July 1, 1996
Creator: Haushalter, R.J.
Partner: UNT Libraries Government Documents Department

Electron Density and Collision Frequency Studies Using a Resonant Microwave Cavity as a Probe

Description: Electron densities and collision frequencies were obtained on a number of gases in a dc discharge at low pressures (0.70-2mm of Hg). These measurements were performed by microwave probing of a filament of the dc discharge placed coaxially in a resonant cavity operating in a TM₀₁₀ mode. The equipment and techniques for making the microwave measurements employing the resonant cavity are described. One of the main features of this investigation is the technique of differentiating the resonance signal of the loaded cavity in order to make accurate measurements of the resonant frequency and half-power point frequencies.
Date: May 1973
Creator: Freeman, Ronald Harold
Partner: UNT Libraries

Self-discharge rate of lithium thionyl-chloride cells

Description: Our low-rate lithium/thionyl-chloride ``D`` cell is required to provide power continuously for up to 10 years. The cell was designed at Sandia National Laboratories and manufactured at Eagle-Picher Industries, Joplin, Missouri. We have conducted accelerated aging studies at elevated temperatures to predict long-term performance of cells fabricated in 1992. Cells using 1.0M LiAlCl{sub 4} electrolyte follow Arrhenius kinetics with an activation energy of 14.6 Kcal/mol. This results in an annual capacity loss to self-discharge of 0.13 Ah at 25 C. Cells using a 1.0M LiAlCl{sub 4}{sm_bullet}SO{sub 2} electrolyte do not follow Arrhenius behavior. The performance of aged cells from an earlier fabrication lot is variable.
Date: December 31, 1993
Creator: Cieslak, W. R.
Partner: UNT Libraries Government Documents Department

Research Studies on Analysis of Ionized Gases. Final Report

Description: The appearance of a large mass 12 peak in pure helium afterglows prompted further investigations, from which it is believed that the maas 12 peak is carbon from a CO impurity, probably a result of outgassing of the walls of the discharge chamber, Mixtures of oxygen with helium and neon have been examined in an attempt to measure the O/sup +/ to O/sub 2/ charge transfer rate. Afterglows in hydrogen, water vapor, and nitrogen-- hydrogen mixtures have also been studied. (auth)
Date: July 31, 1962
Creator: Snow, W. R.
Partner: UNT Libraries Government Documents Department