A first order phase transition between the quark-gluon plasma and the hadron gas can have important consequences for cosmology. These consequences result from the generation of isothermal baryon number density fluctuations as the universe passes through the phase transition. Calculations based upon simple models for the statistical mechanics of the two phases indicate that these fluctuations have large amplitude. The fluctuations persist after completion of the phase transition, being slowly damped by diffusion of baryon number. Upon decoupling of neutrons and protons at temperature T /approximately/ 1 MeV, the neutrons begin to diffuse rapidly out of the dense regions and substantial segregation of the neutrons and protons results. Light element nucleosynthesis then occurs at T /approximately/ 0.1 MeV. It is possible to reconcile the observed abundances of the light elements with model universes in which all of the matter is composed of baryons, the cosmological constant is zero, and the geometry is flat. 12 refs., 2 figs.

At the two previous heavy ion fusion symposia, researchers from Livermore presented their best estimates of target energy gain. The results presented at Tokyo differed significantly from those presented at Darmstadt. The Livermore estimates were again revised for this symposium. The new estimates are given in an accompanying paper by Lindl et al. and in additional detail in this paper. The new estimates are similar to the results presented at Darmstadt. The implications of the new results are discussed.

Heuristic relationships such as the Lawson-Penner criterion, used to scale Free Electron Laser (FEL) amplifier gain and efficiency over orders of magnitude in beam current and brightness, have no fundamental basis. The brightness of a given source is set by practical design choices such as peak voltage, cathode type, gun electrode geometry, and focusing field topology. The design of low emittance, high current electron guns has received considerable attention at Livermore over the past few years. The measured brightnesses of the Experimental Test Accelerator (ETA) and Advanced Test Accelerator (ATA) guns are less than predicted with the EBQ gun design code; this discrepancy is due to plasma effects from the present cold, plasma cathode in the code. The EBQ code is well suited to exploring the current limits of gridless relativistic Pierce columns with moderate current density (<50 A/cm/sup 2/) at the cathode. As EBQ uses a steady-state calculation it is not amenable for study of transient phenomena at the beam head. For this purpose, a Darwin approximation code, DPC, has been written. The main component in our experimental cathode development effort is a readily modified electron gun that will allow us to test many candidate cathode materials, types and …

A heavy ion beam propagating through a hard or near vacuum (< 10/sup -3/ torr) is subject to emittance growth due to the phase space distortions caused by anharmonic self-forces. If the distortion remains uncorrected, an enlarged focal spot results. Analytic predictions of an increase in rms emittance and focal spot size are given for the hard vacuum case and are shown to agree with computer simuations for initially cold beams. Some effects of the beam preconditioning in the region from accelerator output to final focusing magnet are discussed. For the case of near vacuum transport (10/sup -4/ to 10/sup -3/ torr), prediction of final focal spot size requires consideration of additional effects such as beam stripping to high charge state and charge neutralization by electrons which are produced internally in the vessel and/or are injected from outside.

Variations in soil loss as a function of certain land use and land management practices were investigated on a small watershed in the Texas Panhandle using CREAMS, a recently developed computer model capable of simulating dynamic rainfall, runoff, and erosion processes over the time-frame of decades. Simulations of different curve numbers, three types of cropping, and varying crop yield and plowing practices were made to determine the sensitivity of soil loss to these parameters. Comparisons were made to actual in-field measurements of soil loss on experimental plots. 8 references, 3 figures.

Separate abstracts are prepared for twelve papers presented at the symposium. (MCW)

We consider a class of problems, notably double ionization, which require accurate descriptions of correlation in both the initial and final states. Methods are presented for representing correlated wavefunctions on a basis spline lattice, and for calculating bound-continuum transition probabilities. 13 refs.

Corrections to the naive prediction for the inclusive semihadronic decay rate of the /tau/ lepton contain several surprises: electroweak corrections are significant, nonperturbative QCD corrections can be treated systematically, and the order ed /sub s/T perturbative QCD corrections are enormous. The possibility of precise theoretical predictions of the decay rate is discussed. 10 refs.

Two x- and gamma-ray systems were recently installed at-line in gloveboxes and will measure Pu solution concentrations from 5 to 105 g/L. These NDA technique, developed and refined over the past decade, are now used domestically and internationally for nuclear material process monitoring and accountability needs. In off- and at-line installations, they can measure solution concentrations to 0.2%. The K-XRFA systems use a transmission source to correct for solution density. The gamma-ray systems use peaks from 59- to 208-keV to determine solution concentrations and relative isotopics. A Pu check source monitors system stability. These two NDA techniques can be combined to form a new, NDA measurement methodology. With the instrument located outside of a glovebox, both relative Pu isotopics and absolute Pu abundances of a sample located inside a glovebox can be measured. The new technique works with either single or dual source excitation; the former for a detector 6 to 20 cm away with no geometric corrections needed; the latter requires geometric corrections or source movement if the sample cannot be measured at the calibration distance. 4 refs., 7 figs., 2 tabs.

The two-year Mirror Advanced Reactor Study (MARS) has resulted in the conceptual design of a commercial, electricity-producing fusion reactor based on tandem mirror confinement. The physics basis for the MARS reactor was developed through work in two highly coupled areas of plasma engineering: magnetics and plasma performance.

Instabilities with frequencies in the neighborhood of the electron cyclotron frequency are of interest in determining stable operating regimes of hot-electron plasmas in EBT devices and in tandem mirrors. Previous work used model distributions significantly different than those suggested by recent Fokker-Planck studies. We use much more realistic model distributions in a computer code that solves the full electromagnetic dispersion relation governing longitudinal and transverse waves in a uniform plasma. We allow for an arbitrary direction of wave propagation. Results for the whistler and upper-hybrid loss-cone instabilities are presented.

Since 1978 the United States Department of Energy's Atmospheric Studies in Complex Terrain program has conducted research fundamental to a better understanding of atmospheric transport and diffusion in complex topographies. Expertise in atmospheric physics theory, computer modeling, laboratory modeling, and field experimentation have been integrated into a balanced program. The initial emphases of the research were on nocturnal drainage winds, the effect terrain has on them, and their interactions with external flows. Highlights of some physical concepts of nocturnal drainage winds, derived mainly from the results of the field experiments, are presented. 21 references, 11 figures.

The incentives for separating and eliminating various elements from radioactive waste prior to final geologic disposal were investigated. Exposure pathways to humans were defined, and potential radiation doses to an individual living within the region of influence of the underground storage site were calculated. The assumed radionuclide source was 1/5 of the accumulated high-level waste from the US nuclear power economy through the year 2000. The repository containing the waste was assumed to be located in a reference salt site geology. The study required numerous assumptions concerning the transport of radioactivity from the geologic storage site to man. The assumptions used maximized the estimated potential radiation doses, particularly in the case of the intrusion water well scenario, where hydrologic flow field dispersion effects were ignored. Thus, incentives for removing elements from the waste tended to be maximized. Incentives were also maximized by assuming that elements removed from the waste could be eliminated from the earth without risk. The results of the study indicate that for reasonable disposal conditions, incentives for partitioning any elements from the waste in order to minimize the risk to humans are marginal at best.

Final acceptance tests of the Mirror Fusion Test Facility (MFTF-B) were completed in February 1986. These tests verified performance of the following subsystems: the magnet system, the vacuum system and vessel, cryogenic systems, 80-keV neutral-beam sources and power supplies, microwave power systems for plasma heating, the supervisory control and diagnostic system, and the local control and instrumentation system. The entire magnet system was operated at full field continuously for 24 hours. The largest field alignment error under full load, determined using an electron beam technique, was 6 mm, well within the required precision of 15 mm. Absolute values of the magnetic field were determined using nuclear magnetic resonance techniques and were found to be within 2% of predicted values. All magnetic protection systems and fault protection systems were tested at full load. At 4.35 K, the cooling capacity of the liquid helium system exceeded the 11 kW rating and the nitrogen reliquifier met its 500 kW rating.

The explanation of SN Type I by radioactive decay of /sup 56/Ni requires a relatively small value of the transparency function M/sub ej//v/sub 9//sup 2/ = 0.22 in units of M/sub solar/'s and 10/sup 9/ cm s/sup -1/ to explain the light curve. A minimum mass of /sup 56/Ni is required to explain the peak and near peak luminosity. Subsequent radioactive decay energy must escape in some other form than optical light in order to explain the rapid early and late time decay. Early ultraviolet and infrared radiation are excluded as sinks of energy by observations. PdV work is excluded by theory. The energy loss due to the escape of gamma rays and ..beta../sup +/'s with the above value of M/sub ej//v/sub 9//sup 2/ gives good agreement with the light curve after maximum, provided essentially all the trapped energy is converted to optical light. The peak of SN 1972e is explained with the above transparency value M/sub ej//v/sub 9//sup 2/ = 0.22 and mass of /sup 56/Ni of 0.25 M/sub solar/ or 0.4 M/sub solar/, and a distance of 3.2 Mpc or 4 Mpc, respectively. These values depend critically upon the prediscovery report of Austin (1972), and the assumption again …

We have determined experimentally the fraction of laser light incident on DT filled cryogenic polymer coated and bare glass microsphere targets that is absorbed to produce target heating. Data have been obtained for bare glass and CH and CF polymer coated microspheres at 488 nm and 632 nm laser wavelengths. The measurement technique used and experimental results obtained are presented.

A computer simulation code has been developed and validated at the Lawrence Livermore National Laboratory (LLNL) to predict the performance of a railgun electromagnetic accelerator. The code, called MAGRAC (MAGnetic Railgun ACcelerator), models the performance of a railgun driven by a magnetic flux compression current generator (MFCG). The MAGRAC code employs a time-step solution of the nonlinear time-varying element railgun circuit to determine rail currents. From the rail currents, the projectile acceleration, velocity, and position is found. The MAGRAC code was validated through a series of eight railgun tests conducted jointly with the Los Alamos Scientific National Laboratory. This paper describes the formulation of the MAGRAC railgun model and compares the predicted current waveforms with those obtained from full-scale experiments.

Synchrotron radiation measurements of near-threshold and broad-range (20 eV - 3 keV) absolute photoabsorption cross sections were made at the Brookhaven National Laboratory (NSLS) and at Stanford (SSRL). Transmission data for well-characterized multilayer foils provided absolute cross sections with 10% overall uncertainties and better than 0.2% energy resolution. Several examples of our results are presented.

From the outset in the 1950's, fusion research has been motivated by environmental concerns as well as long-term fuel supply issues. Compared to fossil fuels both fusion and fission would produce essentially zero emissions to the atmosphere. Compared to fission, fusion reactors should offer high demonstrability of public protection from accidents and a substantial amelioration of the radioactive waste problem. Fusion still requires lengthy development, the earliest commercial deployment being likely to occur around 2025-2050. However, steady scientific progress is being made and there is a wide consensus that it is time to plan large-scale engineering development. A major international effort, called the International Thermonuclear Experimental Reactor (ITER), is being carried out under IAEA auspices to design the world's first fusion engineering test reactor, which could be constructed in the 1990's. 5 figs., 3 tabs.

This paper describes the design and preliminary testing of a cryogenic cooling loop that uses a thermomechanical pump to circulate superfluid liquid helium. The cooling loop test apparatus is designed to prove forced liquid helium flow concepts that will be used on the Astromag superconducting magnet facility.

A study was undertaken using SAS software to investigate the origin of anomalous temperature measurements recorded by thermocouples (TCs) in an instrumented fuel assembly in a liquid-metal-cooled nuclear reactor. SAS macros that implement univariate and bivariate spectral decomposition techniques were employed to analyze data recorded during a series of experiments conducted at full reactor power. For each experiment, data from physical sensors in the tests assembly were digitized at a sampling rate of 2/s and recorded on magnetic tapes for subsequent interactive processing with CMS SAS. Results from spectral and cross-correlation analyses led to the identification of a flow rate-dependent electromotive force (EMF) phenomenon as the origin of the anomalous TC readings. Knowledge of the physical mechanism responsible for the discrepant TC signals enabled us to device and justify a simple correction factor to be applied to future readings.

With the demonstration of large current densities extracted from hydrogen-discharge-type negative ion sources there has been a new emphasis directed toward the further development of these volume-type sources. Along with this emphasis has been a rapid increase in our understanding of the underlying atomic processes that occur in hydrogen-negative-ion discharges, together with a rapid evolution of the geometric configuration of these ion sources. An account of the development of the atomic processes in negative hydrogen discharges has been given in a recent review. Here we shall emphasize these atomic developments as they bear on the tandem high-density ion-source configuration. 32 refs., 10 figs.

Two key experiments in nuclear physics will be discussed in order to illustrate the advantages of the internal target method and demonstrate the power of polarization techniques in electron scattering studies. The progress of internal target experiments will be discussed and the technology of internal polarized target development will be reviewed. 43 refs., 11 figs.

The friction, wear, and corrosion performance of several metallurgical coatings in 200 to 650/sup 0/C sodium are reviewed. Emphasis is placed on those coatings which have successfully passed the qualification tests necessary for acceptance in breeder reactor environments. Tests include friction, wear, corrosion, thermal cycling, self-welding, and irradiation exposure under as-prototypic-as-possible service conditions. Materials tested were coatings of various refractory metal carbides in metallic binders, nickel-base and cobalt-base alloys and intermetallic compounds such as the aluminides and borides. Coating processes evaluated included plasma spray, detonation gun, sputtering, spark-deposition, and solid-state diffusion.