Lapas attēli

14 p


Submitted for publication Sponsored in part by Italian Ministry of Education, Rome (Preprint-599; ETN-89-94688) Avail: NTIS HC A03/MF A01

The results of a calculation of the Delta 1 = 1/2 K-pi and K-pipi amplitudes in quenched lattice QCD with Wilson fermions are presented. The results were obtained on a 20 x 10 sq x 40 lattice at beta = 6.0 for 3 values of the light quark masses and on a 16 cu x 48 lattice at Beta = 6.2 for 2 values of the light quark masses. Within large statistical and systematic uncertainties, results support the observed enhancement. The eye diagrams, from which penguin operators are generated at low scales, are the sources of the enhancement. The possible role played by octet-scalar particles in the quark mass range is discussed. ESA

(Nota-Interna-920; ETN-89-94739) Avail: NTIS HC A03/MF A01

The Poincare covariance of the Hamiltonian of a N-fermion system, in which the two-body interaction is produced by the exchange of a massless vector boson with a nonconstant form factor at vertices, is investigated. The relativistic separation of center-of-mass and internal-motion variables is performed by exploiting an approach developed by Krajcik and Foldy (1974). It is shown that, in order to ensure that the N-termion Hamiltonian (expanded up to the order 1/cs) is the time-translation generator of the Poincare algebra, one requires a correct treatment of the form factor at the order considered, and, for non-commuting particle charges, the inclusion in the potential of three-body terms, whose expression is explicitly derived. Analysis of the effect of such terms is given for baryons and deuterium in the framework of the constituent quark model.


N89-27486# Rome Univ. (Italy). Dipartemento di Fisica.
G. Gratta, A. S. Schwarz, and C. Zaccardelli (California Univ.,
Santa Cruz.) 16 May 1988 56 p Submitted for publication
Sponsored by DOE, Washington, DC
(Nota-Interna:914; ETN-89-94733; SCIPP-88/04) Avail: NTIS

The possible applications of high resolution vertex detectors at B meson factories based on el +) e(-) collisions are discussed with special emphasis on the different possible kinematic regions (Upsilon (4S) resonance, boosted Upsilon (4S) resonance and e(+) e(-) continuum at 12 to 20 GeV). The observability of B(0) B(0) mixing as a function of the B meson decay length is used to define the minimal requirements on the precision of a vertex detector system. Implications on the design of the detector as well as of the collider are investigated and the technological feasibility of the required spatial resolution is discussed. ESA

N89-27490# Rome Univ. (Italy). Dipartimento di Fisica.
Filippo Ceradini 20 Dec. 1988 21 p Presented at the Perugia
Workshop on Multiparticle Dynamics, Italy, 21-28 Jun. 1988
(Nota-interna-929; ETN-89-94748) Avail: NTIS HC A03/MF

Features of inelastic proton-antiproton collisions at the CERN SPS collider are studied with the UA1 detector using magnetic and calorimetric analysis. Results on charged particle multiplicities, on transverse and longitudinal momenta, and on transverse energy distributions at center of mass energies 0.2 to 0.9 TeV are presented. The same variables are used to study the multiparticle system (spectators) produced in events with jets of W bosons at root s = 0.63 TeV.


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N89-27491# Washington Univ., Seattle.
Report, 30 Jul. 1986 - 29 Mar. 1988
Gerald Gabrielse 26 Jan. 1989 3 p
(Grant AF-AFOSR-0250-86; AF Proj. 2917)
(AD-A208363; AFOSR-89-0657TR) Avail: NTIS HC A02/MF
A01 CSCL 20/8

The DOD Instrumentation Grant was used to purchase equipment for antiproton experiments and for the production of high frequency microwaves. The antiproton experiments are progressing very nicely. In particular, we have recently cooled antiprotons below 1 eV in energy. Before we started these experiments, the lowest energy antiprotons available had kinetic energies 5 million times higher. The purchased equipment was essential to the antiproton experiments and is being very heavily used. The final version of the millimeter microwave system is completed. It is working although there are still some problems remaining.


26 p

N89-27488# Rome Univ. (Italy). Dipartimento di Fisica.
E. Amaldi, P. Bonifazi, E. Coccia, S. Frasca, D. Gretz, G. V. Pallotino,
G. Pizzella, P. Rapagnagni, F. Ricci, and J. Weber (Maryland Univ.,
College Park.) et al 5 Jul. 1988

Sponsored by the
Instituto Nazionale di Fisica Nucleare, Italy; CNR, Italy and NSF,
Washington, DC
(Nota-Interna-918; ETN-89-94737) Avail: NTIS HC A03/MF

The data recorded by the gravitational wave and by the neutrino detectors were analyzed from 22 February 0 hr UT to 23 February 8 hr UT 1987. A correlation is found at the Mont Blanc time with features very similar to that already found using the Mont Blanc data if a time of 8 sec is added to the time recorded on the Kamiokande magnetic tape. This time difference is in agreement with the time difference between the IMB and Kamiokande signals. The probability that the above correlation be due to change is estimated to be of the order of a few percent.




Includes elementary and nuclear particles; and reactor theory.

For space radiation see 93 Space Radiation.

28 p

N89-27492# Sandia National Labs., Albuquerque, NM.
D. L. Fehl, J. R. Lee, R. J. Leeper, M. A. Hedemann, and W. A.
Stygar 1989

Presented at the Instrumentation for Nuclear Weapons Effects Testing Conference, Monterey, CA, 5 Jun. 1989 (Contract DE-ACO4-76DP-00789) (DE89-009327; SAND-89-0188C; CONF-890694-1) Avail: NTIS HC A03/MF A01

New X-ray diagnostics are needed to probe the efficiency of a modern pulsed-power, flash X-ray simulator. In this talk we shall examine some of the critical diagnostic issues which pertain to the SATURN facility located at Sandia National Laboratories. Two

N89-27489# Rome Univ. (Italy). Dipartimento di Fisica.
M. De Sanctis, R. Mignani, and D. Prosperi 13 Jul. 1988
Prepared in cooperation with Istituto Nazionale di Fisica Nucleare,
Rome, Italy

42 P

critical modulation amplitude in monocrystalline Nb/V and Ta/V superlattices; and a strong voltage dependence of the conductivity in granular aluminum are discussed.


new X-ray cameras have been developed for this simulator. A multiframe pinhole camera will be described in a companion talk at this conference. This talk focuses on a one-dimensional camera based on a fast scintillator array. I shall describe its construction, operation, and relative calibration. These cameras together have given us valuable insights into the workings of the SATURN X-ray source, and we shall examine in some detail the results from a SATURN experiment.


N89-27496# Rome Univ. (Italy). Dipartimento di Fisica.
P. Baratti 11 Jul. 1988 28 p
(Nota-Interna-919; ETN-89-94738) Avail: NTIS HC A03/MF

The effect of beam-gas background on L3 experiment is evaluated, computing the rates on individual detectors, and the rejection performance of first level energy trigger. A simulation with Decay-Turtle and Sigel3 programs was done. It uses a complete description of the upward beam line until 640 m from the interaction point and the detailed geometry of L3 setup. Full detector response was considered to produce the trigger data. They were later analyzed with the code that simulates the trigger logic algorithms.


8 p


N89-27493# Los Alamos National Lab., NM. RECENT PROGRESS IN THE LOS ALAMOS KIF PROGRAM T. E. McDonald, D. C. Cartwright, S. V. Coggeshall, C. A. Fenstermacher, J. F. Figueira, L. R. Foreman, P. D. Goldstone, D. E. Hanson, D. B. Harris, and A. A. Hauer et al 1988 Presented at the 12th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Nice, France, 12-19 Oct. 1988 (Contract W-7405-eng-36) (DE88-016235; LA-UR-88-2743; CONF-881015-7; IAEA-CN-50/B272) Avail: NTIS HC A02/MF A01

The goal of the Inertial Confinement Fusion Program (ICF) is to develop the ability to ignite and burn small masses of thermonuclear fuel. Although the present near-term objectives of the program are directed toward defense applications, ICF research continues to be carried out with a view to the longer term goal of commercial power production. The characteristics of a KrF laser make it an attractive candidate as an ICF driver. The KrF wavelength of 248 nm provides a target coupling that is very high at intensities of 10(14) w/sq cm. In addition, the KrF laser can be repetitively operated at frequencies appropriate for a power reactor and has an intrinsically high efficiency, which allows projections to the long-term goal of energy production. The ICF program at Los Alamos consists of driver development, target design and fabrication, and target experimentation. The major effort at present is the investigation and development of KrF technology to determine its applicability for use in a laboratory driver at Los Alamos. Such a driver would be used in defense related technology studies and in areas of scientific study such as highly ionized materials and high energy density physics.


Includes light phenomena; and optical devices. For lasers see 36 Lasers and Masers.

6 p

N89-27497 Department of the Air Force, Washington, DC.
Stanley D. Battle, inventor (to Air Force) 28 Jun. 1988
Filed 15 Jan. 1986 Supersedes N86-30499(24 - 21, p 3377)
(AD-D013978; US-Patent-4,753,501; US-Patent-Appl-SN-818922)
Avail: US Patent and Trademark Office CSCL 20/6

A fiber optic rotary switching device having a single optical fiber rotatable between a plurality of optical fibers is disclosed. The arrangement for rotating the single optical fiber is designed such that the single optical fiber flexes but does not twist with respect to an end thereof which is fixed to a light source (or, in the alternative to a light detector). As a result, the switching device switches light passing through the single optical fiber to a preselected one of the plurality of optical fibers while simultaneously preventing extraneous light from reaching the other optical fibers.


N89-27494# Los Alamos National Lab., NM.
Theresa A. Cull 1989 16 p Presented at the 9th International
System Safety Conference, Long Beach, CA, 17 Jul. 1989
(Contract W-7405-eng-36)
(DE89-011192; LA-UR-89-1178; CONF-890780-1) Avail: NTIS
HC A03/MF A01

The major design requirement for any space nuclear power system is to minimize the potential for interaction of the radioactive materials with Earth's population and environment. All previous space power systems were launched on expendable launch vehicles (ELVs), so the design emphasis for the General Purpose Heat Source (GPHS) was on surviving the most severe ELV accident environments (launch pad explosion and solid propellant fire) and on surviving accident environments resulting from spacecraft failure (reentry and land impact).


N89-27498# Technische Univ., Eindhoven (Netherlands).
Telecommunication Div.
J. Siuzdak (Instytut Telekomunikacji PW, Warsaw, Poland ) Mar.
1988 44 p
(EUT-88-E-190; ISBN-90-6144-190-0; ISSN-0167-9708;
ETN-89-94778) Avail: NTIS HC A03/MF A01

Optical couplers, used in coherent optical phase diversity systems, are analyzed. On the basis of the coupled modes propagation theory, expressions for the output optical fields are obtained. The signal to noise ratio (SNR) at the output of a receiver using these couplers is computed. The variation of SNR with changes of the coupling coefficient is examined for various couplers. The influence of coupling losses is also investigated. The analysis favors two schemes: a three fiber coupler and a four fiber coupler. When the relative noise intensity (RIN) is substantial the four fiber device is best. Three fiber couplers are best when RIN is negligible.


N89-27495# Technische Univ., Delft (Netherlands). ADVANCED ELECTRON BEAM EVAPORATION Ph.D. Thesis Abraham Jacob Guilla Schellingerhout 1988 124 p Sponsored by Stichting voor Fundamenteel Onderzoek der Materie, Amsterdam, Netherlands (ETN-89-94799) Avail: NTIS HC A06/MF A01

Rate control for electron gun evaporation; mass spectrometer controlled fabrication of Si/Ge superlattices; critical thickness for pseudomorphic growth of Si/Ge alloys and superlattices; fabrication of low-capacitance Josephson-junctions; oxygen concentration and microstructure of granular aluminum; strong electric field effect in granular aluminum; analysis of YBa2Cu3O17-y) thin films on sapphire substrates made by electron beam evaporation; growth and characterization of a sinusoidally modulated Nb/V superlattice;

N89-27499 Department of the Air Force, Washington, DC.
John A. Lake, inventor (to AF) and William B. Heath, inventor (to
AF) 16 Aug. 1988 4p Filed 3 Nov. 1986
(AD-D014047; US-Patent-4,764,003; US-Patent-Appl-SN-925959)
Avail: US Patent and Trademark Office CSCL 11/3

An optical mirror has enhanced reflectivity and reduced thermal distortions when it is composed of a substrate coated with a reflective coating made of an organic superconducting material. The substrate is best constructed of materials which have the most favorable thermal expansion and thermal conduction characteristics at temperatures near O K. such as: silicon, diamond, copper, and sapphire. The reflective coating is only a few microns thick and composed of organometallic compounds and is cooled to superconducting or cryogenic temperatures of less than 100 K.


N89-27500# Carnegie-Mellon Univ., Pittsburgh, PA. Dept. of Electrical and Computer Engineering. TIME-SEQUENTIAL OPTICAL DATA PROCESSING Annual Report, 1 Jan. 1988 - 31 Dec. 1989 David Casasent 1 Feb. 1989 78 p (Contract N00014-86-K-0599) (AD-A207514) Avail: NTIS HC A05/MF A01 CSCL 17/5

Our work has emphasized analog optical processing for three levels of multitarget tracking: target detection, track initiation and target tracking. New algorithms and new optical processing architectures have resulted, and initial quantitative results have been obtained for each phase of the work. A new acousto-optic implementation of our sub-pixel target detection algorithm was devised and tested. This involved a new algorithm and architecture that achieves image registration, interpolation and subtraction. This technique is thus suitable for general image registration applications also. A 2-D Hough transform optical processor is used for track initiation. It allows accumulation of target measurements until sufficient confidence has been established that a target track exists. It provides position and velocity estimates for each target and predictions of the next vector location of each target. A new threshold Hough transform provides improved performance and reduced false alarms in noise. Very impressive results from many multiple targets were obtained. This work is also suitable for general object feature extraction and product inspection applications. We devised a completely new realization of the Joint Probabilistic Data Association Algorithm for multitarget tracking and a most attractive new acousto-optic architecture to achieve this. Finally, a new analogy neural net algorithm and architecture was formulated.


measure features, and analyze the single sensor feature data. The multiple sensor process of geometric registration, multiple sensor feature measurement, and multiple sensor target detection were then applied. Sensor-dependent segmentation processes passed a large fraction of the targets present in the imagery, along with a larger number of regions which did not correspond to any target. FLIR images were segmented based on pixel brightness. A new range image segmentation algorithm was developed which exploited the small-scale planarity of tactical vehicles. The post-segmentation target detection problem was that of partitioning segmented targets from segmented non-target regions. Feature information was processed to accomplish this task. The Bayesian minimum error criterion was adopted as the decision rule. When performance was optimized for all cases, the multiple sensor approaches were found to provide improved performance in all comparative performance measures. GRA N89-27503# Department of the Navy, Washington, DC. EFFICIENT DYNAMIC PHASEFRONT MODULATION SYSTEM FOR FREE-SPACE OPTICAL COMMUNICATIONS Patent Application G. G. Gilbreath, inventor (to Navy) and F. E. Davidson, inventor (to Navy) 9 Sep. 1988 29 p (AD-D014128; US-Patent-Appl-SN-242678) Avail: NTIS HC A03/MF A01 CSCL 25/5

An optical communications system is disclosed for correcting in real-time the wavefront distortions of a beam from a coherent optical transmitting source. The system includes a collimating lens and beam splitter for receiving distorted wavefront signal beam and splitting the beam into a pump beam and a weaker intensity signal beam. The system includes a detector and computer for measuring the beam distortion and specifying a compensatory wavefront. The weaker intensity signal beam is modified in a 2-D spatial light modulator according to a compensatory wavefront. A photo-refractive material is used to couple energy from the pump beam to the compensated wavefront signal beam thereby producing a corrected and intensity-enhanced communications beam. GRA

11 p

N89-27501# Army Lab. Command, Watertown, MA. Material
Technology Lab.
James A. Kidd, Jr. Feb. 1989 29 p
(AD-A207522; MTL-TR-89-14) Avail: NTIS HC A03/MF A01
CSCL 20/6

Four different multimode optical fibers were tested to obtain the following correlations: (1) signal power with bend radius, (2) strain with bend radius, and (3) signal power with strain. The data are presented numerically, graphically, and mathematically. Graded index multimode and step index multimode fibers are discussed. The mechanism for the attenuation of light in optical fiber as a result of macrobending is examined. Three of the tested fibers demonstrated a consistent relationship between flexural strain and light transmissivity and could potentially be inlaid with a curved composite material system for use as the principal component in a stress or strain transducer.


N89-27504*# National Aeronautics and Space Administration.
Langley Research Center, Hampton, VA.
Stephen J. Katzberg Jun. 1989
(NASA-TM-101628; NAS 1.15:101628) Avail: NTIS HC
A03/MF A01 CSCL 20F

An analysis is presented of the effects of scan mirrors on scene orientation or rotation for image forming systems. Some simple vector relationships are presented, which when combined with the anticipated application conditions, make it possible to easily assess image orientation effects resulting from scan mirrors. Examples are cited to demonstrate the application of the analysis.


N89-27505# Sandia National Labs., Albuquerque, NM. Microsensor Research Div. A FIBER OPTIC TEST SYSTEM FOR QUANTUM EFFICIENCY MEASUREMENTS K. B. Pfeifer and M. W. Jenkins May 1989 24 p (Contract DE-AC04-76DP-00789) (DE89-012823; SAND-89-0593) Avail: NTIS HC A03/MF A01

A design for a photodetector quantum efficiency measurement test system is presented. The system hardware and control software are explained and the measurement theory is given. A brief discussion of the operation of the prototype is given. Finally, the article concludes with an example of a quantum efficiency measurement of a sample and a discussion of the errors involved in the measurement.


142 p

N89-27502# Air Force Inst. of Tech., Wright-Patterson AFB,
OH. School of Engineering.
Ph.D. Thesis
Michael C. Roggemann May 1989
(AD-A207577; AFIT/DS/ENP/89-1) Avail: NTIS HC A07/MF
A01 CSCL 17/5

Automatic detection of tactical targets in corresponding sets of non-pixel registered forward-looking infrared (FLIR) sensor images and range sensor images was studied. A processing architecture was developed to address the problems associated with processing non-pixel registered imagery. The architecture used specialized sensor-dependent processing to segment the images,

N89-27506* # National Aeronautics and Space Administration.
Lewis Research Center, Cleveland, OH.
Diane M. Swec and Michael J. Mirtich 1989 16 p Presented
at the 1989 Technical Symposia on Aerospace Sensing, Orlando,
FL, 27-31 Mar. 1989; sponsored by The International Society for
Optical Engineering
(NASA-TM-102111; E-4881; NAS 1.15:102111) Avail: NTIS HC
A03/MF A01 CSCL 20F

Diamondlike carbon (DLC) films were deposited on infrared transmitting optical windows and were evaluated as protective coatings for these windows exposed to particle and rain erosion. The DLC films were deposited on zinc selenide (ZnSe) and zinc sulfide (ZnS) by three different ion beam methods: (1) sputter deposition from a carbon target using an 8-cm argon ion source; (2) direct deposition by a 30-cm hollow cathode ion source with hydrocarbon gas in argon; and (3) dual beam direct deposition by the 30-cm hollow cathode ion source and an 8-cm argon ion source. In an attempt to improve the adherence of the DLC films on ZnSc and ZnS, ion beam cleaning, ion implantation with helium and neon ions, or sputter deposition of a thin, ion beam intermediate coating was employed prior to deposition of the DLC film. The protection that the DLC films afforded the windows from particle and rain erosion was evaluated, along with the hydrogen content, adherence, intrinsic stress, and infrared transmittance of the films. Because of the elevated stress levels in the ion beam sputtered DLC films and in those ion beam deposited with butane, films thicker than 0.1 micron and with good adherence on ZnS and ZnSe could not be generated. An intermediate coating of germanium successfully allowed the DLC films to remain adherent to the optical windows and caused only negligible reduction in the specular transmittance of the ZnS and ZnSe at 10 microns.


Reinoud Felix Wolffenbuttel 1988 114 p
(ETN-89-94800) Avail: NTIS HC A06/MF A01

The possibility of applying the wavelength dependence of the absorption coefficient in silicon for radiation in the visible part of the spectrum for color sensing was investigated. Evaluation of the parasitic wavelength dependences shows that color detectors in silicon with a well-defined, distinct, and reproducible response can be obtained by using an electrical control parameter in a single photodiode. Implementations of the basic color-sensing mechanism are evaluated. The applicability of this sensor in a high-density CCD color imager is restricted by the signal-to-noise ratio. The properties of the two different versions the color indicator are also discussed. The measured responses are consistent with the results of the simulations. The ratio-type of color indicator has the best performance/complexity ratio. ESA

32 p

N89-27507# National Bureau of Standards, Boulder, CO.
Electromagnetic Technology Div.
Lee E. Larson (Denison Univ., Granville, OH.), Donald R. Larson,
and Robert J. Phelan, Jr. Aug. 1988 67 p
(PB89-188593; NBSIR-88/3092) Avail: NTIS HC A04/MF A01

A computer controlled system has been developed to measure the intensity profile of optical waveguides. Knowledge of the intensity profile provides an indication of the shape of the waveguide, and therefore the degree to which light can be coupled to the guide from an optical fiber. The report describes the construction and operation of the system.


N89-27510# Naval Research Lab., Washington, DC. Optical
Techniques Branch.
A. Dandridge, A. B. Tveten, A. M. Yurek, A. D. Kersey, and E. C.
McGarry (Sachs/Freeman Associates, Inc., Landover, MD.) 3
May 1989
(AD-A208448; NRL-MR-6457) Avail: NTIS HC A03/MF A01
CSCL 20/6

This report demonstrates the multiplexing of fiber optic interferometric sensors using a CW phase generated carrier technique. The technique employs modulated diode laser sources at different carrier frequencies, near balanced interferometers (approx. 4 cm path difference) and phase generated carrier demultiplexing demodulation. This approach leads to a simple all-passive sensor array which has intrinsically low crosstalk. The system is analyzed in terms of shot noise performance and crosstalk. An experimental all optical implementation of a four sensor array was demonstrated; both the single sensor and multisensor arrays were limited by the laser phase noise to a sensitivity of approx. 18 micro rad/(sqrt Hz). Crosstalk between individual channels was better than -60 dB. In the absence of laser phase/noise the demodulator/demultiplexer demonstrated approx. 2 microrad performance with both single sensor and four element array operation, and 4 microrad performance with 8 elements in operation.



Includes magnetohydrodynamics and plasma fusion.

For ionospheric plasmas see 46 Geophysics. For space plasmas see 90 Astrophysics.

12 p

15 p

N89-27508# Argonne National Lab., IL. Materials Science Div. MAGNETO-OPTICAL PROPERTIES OF ULTRATHIN FERROMAGNETIC FILMS S. D. Bader, E. R. Moog, C. Liu, and J. Zak Apr. 1989 Presented at the Spring Meeting of the Materials Research Society, Symposium on Magneto-Optic Data, San Diego, CA, 24-29 Apr. 1989 (Contract W-31-109-eng-38) (DE89-014640; CONF-890426-20) Avail: NTIS HC A03/MF A01

The surface magneto-optic Kerr effect (SMOKE) has been used to explore the properties of ultrathin ferromagnetic films. The ultrathin regime corresponds to thicknesses less than the depth penetration of light and includes the monolayer range. The ultrathin regime possesses unique magneto-optic properties: the Kerr rotation and ellipticity, in general, behave differently than in the thick film limit. Measurements and simulation in the longitudinal geometry for bcc Fe on Au(100) provide a dramatic example of the metallic reflector enhancement effect due to the nonmagnetic Au underlayer. The rotation enhancement is accompanied by a high reflectivity, as opposed to being at the expense of the reflectivity. Measurements in both polar and longitudinal geometries for epitaxially-stabilized fcc Fe films grown on Cu(100) and Pd(100) indicate the presence of perpendicular surface anisotropy, which suggests new approaches to realizing vertical data-storage media.


N89-27511# Nagoya Univ. (Japan). Inst. of Plasma Physics.
K. Toi, K. Adati, R. Akiyama, A. Ando, R. Ando, T. Aoki, D. G. Bi,
J. Fujita, Y. Hamada, and S. Hidekuma (National Lab. for High
Energy Physics, Tsukuba, Japan ) et al Jan. 1989
Presented at the 16th European Conference on Controlled Fusion
and Plasma Physics, Venice, Italy, 13-17 Mar. 1989
(IPPJ-898; ISSN-0469-4732) Avail: NTIS HC A03/MF A01

The H-mode is observed in a circular cross-section plasma bounded by a limiter on the JIPP T-IIU tokamak. This H-mode is achieved in the smallest tokamak and also in the highest density regime up to 10(14) cm(-3). The rapid current ramp-down during the additional heating considerably reduces the threshold power to the transition.


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N89-27509# Technische Univ., Delft (Netherlands).

(Contract DE-AC04-76DP-00789) (DE89-009325; SAND-89-0670C; CONF-880929-11) Avail: NTIS HC AO2/MF A01

TORE SUPRA is a fairly large tokamak and has an original goal to withstand a large power removal (25 MW) during a 30 seconds long pulse. One of the main energy removal systems is the inner first wall which was originally designed for the following aims: protect the inner side of the vacuum vessel from normal plasma operation (participates to the plasma power removal) and against disruptive events (plasma energy quench and current decay); act as a toroidal belt limiter during steady state operation and plasma start up; and protect the vacuum vessel from the shine through of the neutral beam injectors and act as a beam dump for short shots. In order to match those different goals the design choice was oriented towards an actively cooled graphite wall capable to sustain an 1 MW/m(2) continuous heat flux. This paper discusses this design concept further.


N89-27516# Sandia National Labs., Albuquerque, NM. Thermophysical Properties Div. THERMOPHYSICAL PROPERTIES OF ADVANCED CARBON MATERIALS FOR TOKAMAK LIMITERS E. P. Roth, R. D. Watson, M. Moss, and W. D. Drotning Apr. 1989 142 p (Contract DE-AC04-76DP-00789) (DE89-012799; SAND-88-2057) Avail: NTIS HC A07/MF A01

A plasma limiter is used to control the plasma size in Tokamak fusion research devices and serves as the primary area of plasma wall interaction. Contact with the plasma produces very high heat fluxes, typically 500 to 5000 W/sq cm for pulse lengths of 1 to 10 seconds. Wall temperatures can reach as high as 3000 K resulting in significant melting or wall erosion. Graphite and graphite composites have been chosen as the materials that best meet the requirements of this severe environment. Measurement of the thermophysical properties of these materials is critical to the modeling of the thermal response of the limiters during operation. The thermal diffusivities, thermal conductivities and thermal expansions of several candidate materials were measured. The categories of materials investigated in this study were pyrolytic graphite and annealed pyrolytic graphite; fine-grained graphites; anisotropic carbon/carbon fiber composites; two-directionally woven fibers with a graphitized pitch matrix; and carbon/carbon fiber composites with a four-directionally woven carbon fiber wave. The thermal conductivities of the carbon/carbon fiber composites were determined as a function of fiber orientation. Conductivities were measured using both the laser flash diffusivity technique and the thermal comparative method. The advantages and disadvantages of each of these methods are discussed and the data compared.


N89-27513# Helsinki Univ. of Technology, Espoo (Finland). Dept. of Technical Physics. DYNAMICS OF DOUBLE STIMULATED BRILLOUIN SCATTERING T. J. H. Paettikangas and R. R. E. Salomaa 1988 34 p (PB89-146369; TKK-F-A638; ISBN-951-754-704-8) Avail: NTIS HC A03/MF A01 CSCL 201

The pump wave reflected from the overdense plasma may play an important role in the dynamics of stimulated Brillouin scattering. The particular case of Double Stimulated Brillouin Scattering (DSBS) suggested by Zozulya, Silin, and Tikhonchuk is studied in detail. In DSBS the incident pump wave and the reflected pump wave scatter from a common ion acoustic wave. Some steady state properties of DSBS are reviewed. The analysis of DSBS dynamics is based on a series of numerical experiments. At small pump intensities the system asymptotically approaches a true steady state. When the intensity is increased the solution turns into a regular pulse train with intensity dependent period. Connections between the pulses and soliton-like solutions of a damped sine-Gordon equation are discussed.


N89-27514 Department of the Air Force, Washington, DC.
James P. OLoughlin, inventor (to Air Force) 20 Dec. 1988 9p
Filed 12 Jun. 1987
(AD-D013990; US-Patent-4,792,732; US-Patent-Appl-SN-060881)
Avail: US Patent and Trademark Office CSCL 20/9

A plasma generator is disclosed for exciting electrons in the plasma to a uniform energy level. In a preferred embodiment, two sets of mutually perpendicular electrodes surround a container of gas, with one set being driven through a ninety degree phase shifter to establish a circularly polarized field in the space within the container. Alternative means are disclosed for launching circularly polarized RF waves into the container of gas. A desired level of uniform electron energy is achieved by establishing the proper relationship between the frequency and magnitude of the applied circularly polarized field and the mean free path of the electrons in the plasma.


N89-27517# Colorado Univ., Boulder. Dept. of Astrophysical,
Planetary and Atmospheric Sciences.
John R. Cary Jun. 1989 14 p
(Contract DE-FG02-85ER-53207)
(DE89-012952; DOE/ER-53207/4) Avail: NTIS HC A03/MF

Progress in four research areas has been achieved. A second-order symplectic integration algorithm has been developed and tested. Use of this algorithm allows integration of systems of Hamiltonian equations of motion to be carried out with much less computation. Vacuum field optimization techniques have been improved. One result of this work is a simple method for calculating magnetic island widths. Studies of alpha particle transport in toroidal confinement systems were initiated. This has been used as a test bed for studies of symplectic integrators. Quantum modifications of separatrix crossing theory were calculated. In addition the principal investigator is organizing a U.S.-Japan conference concerning the use of modern techniques for the study of plasma confinement


N89-27515# Massachusetts Inst. of Tech., Cambridge. Plasma
Fusion Center,
Ronald C. Davidson 1989 70 p Presented at the Nonneutral
Plasma Physics, Washington, DC, 28 Mar. 1988
(Contract DE-FG02-88ER-40465)
(DE89-012403; DOE/ER-40465/T1; CONF-8803133-1) Avail:

This paper presents a survey of the equilibrium, stability and collective oscillation properties of magnetically-confined nonneutral plasmas. Emphasis is placed on summarizing several of the technical advances that have occurred in both theory and experiment since the early 1970's.


N89-27518# Texas Univ., Austin. Inst. for Fusion Studies. EQUILIBRIUM OF A PLASMA IN THE FLUID- AND VLASOV-MAXWELL SYSTEMS Swadesh M. Mahajan and Wann-Quan Li May 1989 11 p (Contract DE-FG05-80ET-53088) (DE89-013315; DOE/ET-53088/372; IFSR-372) Avail: NTIS HC A03/MF A01

It is shown that a recently constructed exact solution of the Vlasov equation describing a plasma with density and temperature gradients can be expressed in terms of the constants of motion. The distribution function is then used to illustrate the differences between a Vlasov and a one fluid description. In fluid theory, only the pressure profile is determined (unless one postulates an equation of state), while the Vlasov description leads to a separate determination of density (g) and temperature (psi) profiles. The equation of state, g = psi the 3-2/beta power, comes out naturally in the latter case.


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