Showing papers on "Power density published in 1980"
02 Dec 1980
TL;DR: In this paper, a promising new electron cyclotron wear oscillator is proposed and analyzed, which utilizes an open resonator cavity containing a gyrating electron beam which translates along an external magnetic field.
Abstract: : In this work, a promising new electron cyclotron wear oscillator is proposed and analyzed. The configuration utilizes an open resonator cavity containing a gyrating electron beam which translates along an external magnetic field. The magnetic field is directed perpendicular to the axis of symmetry of the open resonator. Because the wave-particle interaction volume is extremely large, the total input electron beam power can be high and the power density low.
60 citations
TL;DR: In this paper, a study of electron beam surface melting was conducted and the nature of rapidly quenched microstructure and melt zone geometry parameters (the depth, the width and the length) were related to the beam velocity and the power density and are then compared with predictions of heat flow models.
42 citations
TL;DR: In this paper, a high power density, low prepulse, pulse forming line (PFL) configuration with self-breakdown water dielectric switches is presented, and the design parameters and the results of switching experiments are described.
Abstract: Pulse forming networks for high current particle beam fusion accelerators must produce fast rise time, low jitter, low prepulse, and high voltage power pulses. Conventional water dielectric switching can provide the required rise time and jitter, but has limitations on prepulse and output voltage. A high power density, low prepulse, pulse forming line (PFL) configuration with self-breakdown water dielectric switches is presented. The design parameters and the results of switching experiments are described.
32 citations
TL;DR: In this article, survey of dielectric radio-frequency heaters was conducted at various plants throughout Canada in 1979, where the heaters were used for plastic sealing and for gluing wood pieces.
Abstract: •Surveys of dielectric radio-frequency heaters were conducted at various plants throughout Canada in 1979. The heaters were used for plastic sealing and for gluing wood pieces. The devices operated at frequencies between 4 and 51 MHz and their power output ranged from 0.5 to 90 kW. The intensities of the electric and magnetic fields in the vicinity of 82 devices were measured. A significant number of the devices exposed their operators to the fields having the equivalent power density greater than 1 m W fcm 2 , and some greater than 10 m W fcm 2
22 citations
Patent•
10 Nov 1980TL;DR: An apparatus and method for controlling a plasma etching reaction is described in this article, which is controlled by monitoring the output voltage of an optical detector which is responsive to emissions emanating from the reaction.
Abstract: An apparatus and method for controlling a plasma etching reaction. The plasma reaction is controlled by monitoring the output voltage of an optical detector which is responsive to emissions emanating from the reaction. As the output of the detector changes indicating that the first portion of the etching process has been completed, the average power density supplied to the reaction is reduced by switching the applied power from a continuous wave to a pulsed mode. The reaction is allowed to continue to completion in the reduced power mode.
22 citations
TL;DR: In this article, simultaneous solutions of the differential equations governing electron energy and power flow are used to study D region absorption effects arising from high-power HF heating, and it is shown that self-absorption of the heating wave can severely limit HF heating of the upper ionosphere.
Abstract: Simultaneous solutions of the differential equations governing electron energy and power flow are used to study D region absorption effects arising from high-power HF heating. It is shown that self-absorption of the heating wave can severely limit HF heating of the upper ionosphere and that the power density available for heating above the D region saturates as the heating power is increased. Models of the electron temperature distribution under heated conditions are used to compute the change in two-way integral absorption on a 2.4-MHz diagnostic wave due to HF heating as a function of heating frequency. The predicted theoretical absorption change is found to agree with experimental results.
19 citations
TL;DR: In this paper, a detailed knowledge of vacuum spark progress and sample erosion processes is described and their analytical application to layers (thickness 0.1-10 μ) is demonstrated.
18 citations
TL;DR: The spatial properties of an 80-W Nd:YAG laser beam have been measured and a simple expression is obtained which can be used to describe the power density of the beam as a function of peak power density and halfwidth at half-maximum.
Abstract: The spatial properties of an 80-W Nd:YAG laser beam have been measured. A simple expression is obtained which can be used to describe the power density of the beam as a function of peak power density and halfwidth at half-maximum.
17 citations
TL;DR: In this article, the design and operation of a compact superatmospheric pressure CO2 laser operating at ⩽50 Hz was described, at 5 atm singlemode power densities of 300 MW l−1 with a simple excitation circuit with low charging voltage.
Abstract: The design and operation of a compact superatmospheric‐pressure CO2 laser operating at ⩽50 Hz is described. At 5 atm single‐mode power densities of 300 MW l−1 have been achieved at 25 Hz using a simple excitation circuit with low charging voltage.
15 citations
TL;DR: In this paper, a detailed linear and non-linear analysis of quasi-mode parametric excitations relevant to experiments in supplementary heating of tokamak plasmas is presented.
Abstract: A detailed linear and non-linear analysis of quasi-mode parametric excitations relevant to experiments in supplementary heating of tokamak plasmas is presented. The linear analysis includes the full ion-cyclotron harmonic quasi-mode spectrum. The non-linear analysis, considering depletion of the pump electric field, is applied to the recent Alcator A heating experiment. Because of the very different characteristics of a tokamak plasma near the wall (in the shadow of the limiter) and inside, the quasi-mode excitations are studied independently for the plasma edge and the main bulk of the plasma, and for two typical regimes in overall density, the low (peak in density, n0 = 1.5 × 1014 cm−3) and high (n0 = 5 × 1014cm−3)density regimes. At the edge of the plasma and for the low-density regime, it is found that higher nz(nz = c kz/ω) than those predicted by the linear theory are strongly excited. Inside the plasma, the excitation of higher wave numbers is also significant. These results indicate that a large amount of the RF-power may not penetrate to the plasma centre, but will rather be either Landau-damped on the electrons or mode-converted into thermal modes, close to the plasma edge. Moreover, for sufficiently high peaks in density, it is found that all the RF-power is mode-converted before reaching the plasma centre. Inside the plasma, the power density of the excited sideband fields is shown to be always very small in comparison with their excitation at the plasma edge.
13 citations
Patent•
26 Aug 1980
TL;DR: In this paper, a process for controlling the dihydride and monohydride bond densities in hydrogenated amorphous silicon produced by reactive rf sputtering of a target is described.
Abstract: A process for controlling the dihydride and monohydride bond densities in hydrogenated amorphous silicon produced by reactive rf sputtering of an amorphous silicon target. There is provided a chamber with an amorphous silicon target and a substrate therein with the substrate and the target positioned such that when rf power is applied to the target the substrate is in contact with the sputtering plasma produced thereby. Hydrogen and argon are fed to the chamber and the pressure is reduced in the chamber to a value sufficient to maintain a sputtering plasma therein, and then rf power is applied to the silicon target to provide a power density in the range of from about 7 watts per square inch to about 22 watts per square inch to sputter an amorphous silicon hydride onto the substrate, the dihydride bond density decreasing with an increase in the rf power density. Substantially pure monohydride films may be produced.
TL;DR: The I2 stabilized Ar+ laser is now an internationally accepted frequency or wavelength standard having the wavelength?a3 = 514.673 467 nm as mentioned in this paper, and the intrinsic frequency uncertainty is now less than 10-11?.
Abstract: The I2 stabilized Ar+ laser is now an internationally accepted frequency or wavelength standard having the wavelength ?a3 = 514.673 467 nm. Using an improved stabilization scheme the intrinsic frequency uncertainty is now less than 10-11 ?. A Fabry-Perot prestabilization circuit reduces the effective laser linewidth from 2 MHz to 70 kHz. Therefore, the iodine cell can be operated at a lower I2 vapor pressure of 1 Pa yielding narrower I2 reference signals. In order to avoid power shifts, the power density inside the iodine cell was reduced to 0.3 mW/mm2 by expanding the beam diameter. The resulting improved signal-to-noise ratio also allowed to measure the frequency separation of 13 isolated 127I2 hyperfine components of the P(13) 43-0 absorption line with an uncertainty of less than 1 kHz.
TL;DR: In this article, the annealing effect of laser pulses from ruby and neodymium glass lasers on ion implanted 57Fe in silicon is investigated by Mossbauer conversion electron spectroscopy.
Abstract: The annealing effect of laser pulses from ruby and neodymium glass lasers on ion implanted 57Fe in silicon is investigated by Mossbauer conversion electron spectroscopy. For light pulses (≈ 70 ns duration time) from a ruby laser with a power density of 1.5 J/cm2, the Mossbauer spectrum changes drastically upon irradiation. After the irradiation, a quadrupole doublet is observed. This is interpreted to be due to the precipitation of FeSi compounds of approximately FeSi2 composition. From anodic stripping of surface layers it is found that these precipitates are formed in a shallow surface layer of ⪅ 200 A. The results are explained by the assumption that a surface layer of the silicon is molten. For light pulses from a Nd laser (≈ 100 ns duration time), the same result as for a ruby laser is obtained for power densities ⪆ 10 J/cm2. For lower power densities the Mossbauer spectra change only slightly but the implant with an average depth of ≈ 650 A is found to move towards the surface to an average depth of ≈ 300 A.
TL;DR: In this article, an electron-beam excited supersonic flow at very low temperature and high density was used to achieve quasi-cw laser action at several wavelengths near 308 nm.
Abstract: Quasi cw laser action has been achieved at several wavelengths near 308 nm in an electron‐beam excited supersonic flow at very low temperature and high density. The 0–1, 0–2, and 0–3 XeCl laser emissions have been obtained when Ne/Xe/HCl mixtures aerodynamically cooled to 120 K and at a density up to 1.7 amagat were excited by an electron beam of medium intensity (jeb≃10 A cm−2, 600 ns). Up to 15 mj of laser energy (≃1 J/l) was extracted in 500‐ns pulses from the 16‐cm long and 1‐cm‐diam useful volume of this laser. The highest intrinsic efficiency (laser energy out / e‐beam energy deposited in the active medium) observed was over 2.5%.
TL;DR: In this article, the authors present the concept of dielectric power conversion using pyroelectric properties of ferroelectric materials in three ways: (1) high power density i s to be achieved by utilizing the full swing of polarization reversal rather than small changes around the spontaneous polarization value; hysteresis loss which normally occurs in polarization reversal is minimized by use of a series inductor which prevents excessively rapid reversal and its attendant frictional loss, the energy being stored instead in the inductor, and high intrinsic efficiency is achieved by using a near Carnot thermal cycle,
Abstract: Since 1975, the present concept of dielectric power conversion has been under development. It differs from earlier concepts using pyroelectric properties of ferroelectric materials in three ways: (1) high power density i s to be achieved by utilizing the full swing of polarization reversal rather than small changes around the spontaneous polarization value; hysteresis loss which normally occurs in polarization reversal is to be minimized by use of a series inductor which prevents excessively rapid reversal and its attendant frictional loss, the energy being stored instead in the inductor, (2) high intrinsic efficiency is to be achieved by use of a near Carnot thermal cycle, (3) high overall efficiency is to be achieved by use of multiple staging; reed valves like those used in outboard engines are employed to pulse the heat between successive capacitors.
TL;DR: In this paper, the gaussian shape of a light pulse is distorted in a laser spark, and a narrowing pulse appears with an amplitude enlarged by an order of magnitude due to self-focusing.
TL;DR: In this paper, the power density radiation patterns of shear and longitudinal bulk modes were computed as functions of the radiation angle, the electrode metallization ratio, and the frequency.
Abstract: Radiation patterns of bulk acoustic modes from a finite in- terdigital transducer on Y-Z LiNb03 were found using moment method and then compared with the experimental results. The power density radiation patterns of shear and longitudinal bulk modes were computed as functionsof the radiation angle, the electrode metallization ratio, and the frequency. It was shown that a SAW transducer can be very effi- ciently used for shear bulk wave excitation. For instance, at the sec- ond harmonic of the Rayleigh wave the percentage power of the shear, longitudinal, and SAW is 67.2,26.4, and 6.4 percent, respectively. The bulk power density distribution versus radiation angle does not change in form with a change in the metallization ratio. The SAW power density increases with increasing values of the metallization ratio.
18 Dec 1980
TL;DR: The Tandem-Mirror-Next-Step (TMNS) as discussed by the authors is a deuterium-tritium (D-T) burning, tandem-mirror device with a fusion power output of 245 MW.
Abstract: The Tandem-Mirror-Next-Step (TMNS) facility is designed to demonstrate the engineering feasibility of a tandem-mirror reactor The facility is based on a deuterium-tritium (D-T) burning, tandem-mirror device with a fusion power output of 245 MW The fusion power density in the central cell is 21 MW/m/sup 3/, with a resultant neutron wall loading of 05 MW/m/sup 2/ Overall machine length is 116 m, and the effective central-cell length is 509 m The magnet system includes end cells with yin-yang magnets to provide magnetohydrodynamic (MHD) stability and thermal-barrier cells to help achieve a plasma Q of 47 (where Q = fusion power/injected power) Neutral beams at energies up to 200 keV are used for plasma heating, fueling, and barrier pumping Electron cyclotron resonant heating at 50 and 100 GHz is used to control the electron temperature in the barriers Based on the resulting engineering design, the overall cost of the facility is estimated to be just under $1 billion Unresolved physics issues include central-cell beta-limits against MHD ballooning modes (the assumed reference value of beta exceeds the current theory-derived limit), and the removal of thermalized cap alpha-particles from the plasma
Patent•
08 Sep 1980
TL;DR: In this article, a ship is provided with a propeller driven by a shaft of a power generator operated by the main engine, and the exhaust gas from a main engine is discharged from a fumeel having an economizer.
Abstract: PURPOSE:To control a drum pressure in a discharge gas economizer in reference to a predetermined value by a method wherein a thermal energy of exhaust gas from a main engine is completely recovered, a power value is always responded instantaneously to a variation of power load spent in the ship so as to keep the frequency of the system constant. CONSTITUTION:The ship is provided with a propeller 1 driven by a shaft of a power generator 2 operated by the main engine which is directly connected to the main engine 3, and the exhaust gas from the main engine 3 is discharged from a fumel 4 having an economizer 5 therein. Steam produced by the economizer 5 performs a work in an exhaust gas steam turbine 8 so as to operate an exhaust gas turbo power generator 9. During this operation, a power E of said power generator 9 which may be generated is measured by a contrl unit 17 in response to a volume of evaporation in the economizer 5. When the power E is equal to a demand power Ea for the ship, the power generator 2 is operated under no load, the power is supplied by the power generator 19. In turn, when a relation between E and Ea is E>Ea, the power generator 2 is operated as an electric motor, and to the contrary when a relation between E and Ea is E
TL;DR: A quasi-cw plasma jet, initiated by CO2-laser radiation of power density 0.1-2 MW/cm2 on a graphite target in air, was investigated using spectroscopic, interferometric, and photometric diagnostic methods as mentioned in this paper.
Abstract: A quasi-cw plasma jet, initiated by CO2-laser radiation of power density 0.1–2 MW/cm2 on a graphite target in air, was investigated using spectroscopic, interferometric, and photometric diagnostic methods. The plasma jet was shown to consist of carbon vapor transparent to the laser radiation and propagating into the air surrounding the target without being appreciably heated by the laser radiation. The gasdynamics and thermal physics of the jet are discussed; they are of interest for the problems of laser processing of materials and the construction of laser jet engines.
Patent•
28 Feb 1980
TL;DR: In this paper, the authors proposed to avoid the system down with the interruption of power supply of the input and output unit, without providing specific power supply with the inputs and outputs, by supplying power to the output unit from the power supply for CPU.
Abstract: PURPOSE:To avoid the system down with the interruption of power supply of the input and output unit, without providing specific power supply with the input and output unit, by supplying power to the input and output unit from the power supply for CPU. CONSTITUTION:In time sharing control of the input and output control unit IOC with a plurality of CPU CCo...CCn, FFo...FFn indicating whether the control unit IOC is under control or not to CPUCCo... CCn is provided, and the relays DLo...DLn controlled with FFo...FFn are provided. Further, power is fed to the control unit IOC from the power supplies PWo...PWn provided with CPUCCo... CCn via the contacts dlo...dln of the relays DLo...DLn. Thus, with the power supply to the control unit IOC from the power supplies PWo...PWn of CPUCCo... CCn, the systemdown due to power interruption of the control unit IOC can be avoided.
TL;DR: In this article, the lasing spectra and energy characteristics were investigated for a laser operating with the isotopes 12C16O2, 13C16 O2, 12C18O2 and 12C 16O18O.
Abstract: The lasing spectra and energy characteristics were investigated for lasers operating with the isotopes 12C16O2, 13C16O2, 12C18O2, and 12C16O18O. It was found that the output power of a laser utilizing the CO2 isotopes was determined by the content of a particular isotope in the carbon dioxide gas. For equal enrichments, all the isotopes investigated, with the exception of 12C16O18O, gave comparable output powers. The unsaturated gains were identical for the most intense transitions of the symmetric molecules; the gain was a factor of two less for the asymmetric molecule. The gain rose linearly with increasing enrichment. The ultimate specific power output, given by the product of the saturation power density and the gain, was practically independent of the enrichment.
TL;DR: The electrical effects associated with pulsed laser irradiation of thermal oxides of silicon were investigated in this article, where the oxides were irradiated by a repetitively Q-switched Nd 3+ :YAG laser operated at the fundamental frequency.
Abstract: The electrical effects associated with pulsed laser irradiation of thermal oxides of silicon were investigated. Three of the functions performed by thermal oxides are control of field effects, junction passivation and electrical isolation. Representative oxide thicknesses suitable for these applications were studied: ≈ 100 nm; ≈ 500 nm and ≥, 1.0 μm respectively. The oxides were irradiated by a repetitively Q-switched Nd 3+ :YAG laser operated at the fundamental frequency. The key laser parameters of energy and power density were varied over a wide range, from no change to the onset of discernible change and irreversible damage. The range of energy densities over which the oxide was not electrically degraded was established for each thickness of the oxide. This range of energy densities is compared to the useful range of energy densities for annealing polysilicon and for activating an implant through an oxide. The electrical data was obtained using a mercury probe and through the analysis of a large number of MOS capacitors formed on the irradiated oxides. Parameters measured include: breakdown voltages, surface state charge densities and flat band voltages.
TL;DR: In this article, experimental measurements with probes were performed to estimate radial electromagnetic energy flow directed toward a tube axis and plasma heating power for theta pinch discharges, and the time development for the spatial distributions of the electromagnetic.
Abstract: In order to estimate radial electromagnetic energy flow directed toward a tube axis and plasma heating power for theta pinch discharges, experimental measurements with probes were performed. Time development for the spatial distributions of the electromagnetic. energy flow and the plasma heating power density was obtained, so that some interesting phenomena of the theta pinch plasmas were revealed; that is, at the compression phase, the radial distribution of the Poynting vector has a hump under special discharge conditions and total plasma heating power shows a maximum at earlier time than the total electromagnetic input power does.
TL;DR: The laser's primary characteristics of high brightness and good temporal and spatial coherence provide many opportunities for remote sensing applications, especially when allied with its wavelength range (in excess of two decades), regimes of continuous tunability, continuous and pulsed operation, great pointing accuracy and enormous power and power density.
Abstract: The laser's primary characteristics of high brightness and good temporal and spatial coherence provide many opportunities for remote sensing applications, especially when allied with its wavelength range (in excess of two decades), regimes of continuous tunability, continuous and pulsed operation, great pointing accuracy and enormous power and power density. (As has been remarked, an instantaneous power of terawatts from a short pulse (picosecond) laser represents more power than all the power stations of the world put together!).
01 Jan 1980
TL;DR: In this paper, a theoretical model of the power fluctuation at LOFT was developed to determine the power fluctuations' dependence on moderator and doppler coefficient, and predict fluctuation behavior during future operation.
Abstract: Investigation of power fluctuations at LOFT began after peak to peak power fluctuations of 1.5% of full power were observed prior to Loss of Coolant Experiment L2-3. The power fluctuations are caused by fluctuations in primary coolant flow. The fluctuations in coolant flow result in fluctuations in moderator temperature, which through the moderator coefficient of reactivity, cause the power fluctuations. This conclusion is supported experimentally by the high coherence between power and flow, and by the increase in power fluctuation magnitude with steady-state power and with increasing temperature coefficient. A theoretical model of the phenomenon is being developed to determine the power fluctuations' dependence on moderator and doppler coefficient, and predict fluctuation behavior during future operation.
01 Nov 1980
TL;DR: In this paper, the maximum specific power attainable without significant fission-gas release for UO/sub 2/ wafers ranging from 0.75 to 1.50 mm in thickness was determined.
Abstract: The Reduced Enrichment Research and Test Reactor Program is aimed at reducing fuel enrichment to < 20% in those research and test reactors presently using highly enriched uranium fuel. UO/sub 2/ caramel fuel is one of the most promising new types of reduced-enrichment fuel for use in research reactors with very high power density. Parametric studies have been carried out to determine the maximum specific power attainable without significant fission-gas release for UO/sub 2/ wafers ranging from 0.75 to 1.50 mm in thickness. The results indicate that (1) all the fuel designs considered in this study are predicted not to fail under full-power operation up to a burnup of 1.09 x 10/sup 21/ fis/cm/sup 3/; (2) for all fuel designs, failure is predicted at approximately the same fuel centerline temperature for a given burnup; (3) the thinner the wafer, and wider the margin for fuel specific power between normal operation and increased-power operation leading to fuel failure; (4) increasing the coolant pressure in the reactor core could improve fuel performance by maintaining the fuel at a higher power level without failure for a given burnup; and (5) for a given power level, fuel failure will occur earlier at a highermore » cladding surface temperature and/or under power-cycling conditions. 12 figures, 7 tables.« less
TL;DR: In this paper, a general expression for the maximum radiant power density at the receiver of a general optical concentrator in terms of the acceptance function and the input distribution of radiation is obtained.
Abstract: A general expression is obtained for the maximum radiant power density at the receiver of a general optical concentrator in terms of the acceptance function and the input distribution of radiation. As an example of the result, the radiant power density for two- and three-dimensional symmetric and asymmetric ideal concentrators is found without reference to any particular concentrator design. For particular input distributions both two- and three-dimensional ideal asymmetric concentrators have greater power density than their symmetric counterparts.
TL;DR: In this paper, an electromagnetic method for the measurement of the local power density in metallic structures caused by eddy currents was developed, and the method was applied to the case of eddy-currents.
Abstract: This paper develops an electromagnetic method for the measurement of the local power density in metallic structures caused by eddy-currents.