Short sample critical measurements on ISABELLE superconducting cables are described. The purpose is to provide a basis for assessing magnet performance and to provide Quality Assurance data on materials purchases. The measurements are made on 1 m samples in a dipole magnet. Voltages on the V-I curve are determined to a precision of several tenths of a microvolt. The critical current is defined as that at which rho = 1 x 10/sup -12/..cap omega..cm/sup 1/ and is determined to a precision of 1 to 2%. Similar techniques are employed in determining the critical currents of the wires of which the cables are made. The relation between cable and wire critical currents will be discussed. It is found that well insulated, slowly ramped cables of the ISABELLE design are stable for currents up to approximately rho = 2 x 10/sup -12/..cap omega..cm. The value of current corresponding to the resistivity determines the limit of magnet performance. Additional properties of the cabled conductors such as the normal state resistance and the longitudinal quench propagation velocity are also measured.

Experimental and theoretical research has been conducted jointly at the Livermore and Los Alamos National laboratories on dc electromagnetic railgun Lorentz accelerators. Pellets weighing a few grams to tens of grams have been launched at velocities up to better than 11 km/s. The research is addressed to attaining repeated launches of samples at hypervelocity in target impact experiments. In these experiments, shock-induced pressures in the tens of megabars range are obtained for high pressure equation-of-state research. Primary energy sources of the order of several hundred kJ to a MJ and induction currents of the order of 1 or more MA are necessary for these launches. Erosion and deformation of the conductor rails and the accelerated sample material are continuing problems. The heating, stress, and erosion resulting from simultaneous imposition of rail induction current, dense plasma (armature) interaction, current distribution, magnetic field stresses and projectile/rail contact friction are examined. It is found that while frictional heating and consequent sliding contact erosion are minor contributors to the overall erosion process, the same cannot be said for plasma impingement, penetration, and almost simultaneous induction current (Joule) heating.

The Experimental Physics Division (E-Division) at the Lawrence Livermore National Laboratory conducts research in basic and applied nuclear and atomic physics and materials science. Most of the research within the Division utilizes one of three facilities: an intense 14-MeV neutron source, a 27-MeV cyclograaff (consisting of a 15-MeV cyclotron and a 6-MV tandem van de Graaff), and a 100-MeV electron linac. A brief description of each facility is presented with emphasis on the research capabilities presently available.

Double mode pulsation is a very pervasive phenomenon in stars all over the Hertzsprung-Russell diagram. In order of increasing radius, examples are: ZZ Ceti stars, the sun, the delta Scuti stars, RR Lyrae variables, the ..beta.. Cephei variables and those related to them, Cepheids, and maybe even the Mira stars. These many modes have been interpreted as both radial and nonradial modes, but in many cases the actual mode has not been clearly identified. Yellow giants seem to be the most simple pulsators with a large majority of the RR Lyrae variables and Cepheids showing only one pulsation period. We limit this review to those very few cases for classical Cepheids and RR Lyrae variables which display two modes. For these we know many facts about these stars, but the actual cause of the pulsation in two modes simultaneously remains unknown.

Fusion research has matured during the last decade and significant insight into the future program needs has emerged. While some will properly note that the crystal ball is cloudy, it is equally important to note that the shape and outline of our course is discernable. In this short summary paper, I will draw upon the National Mirror Program Plan for mirror projects and on available design studies of these projects to put the specific needs of the mirror program in perspective.

Since the discovery of numerous double-mode RR Lyrae variables in the globular cluster M15 by Cox, Hodson, and Clancy (1981a and 1983, CHC), double-mode behavior in these Population II variables has made it possible to theoretically determine their masses, composition, and maybe even their evolution direction. The most unusual characteristic of these new double-mode pulsators is that they are found in a narrow range of first overtone periods (P/sub 1/=0./sup d/38-0./sup d/43) and period ratios (P/sub 1//P/sub 0/=0.746+-0.001), where P/sub 0/ is the fundamental mode period. This compares with P/sub 1/=0./sup d/41 and P/sub 1//P/sub 0/=0.746 for AQ Leonis, the only known field double-mode RR Lyrae star. Recent linear studies by CHC (1981a and 1983) suggest that double-mode behavior in this class of stars results from mode switching between the fundamental (F) and first overtone (1H) radial pulsation modes at the transition line just to the red of the F-mode blue edge.

A convective overshooting at the edge of the turbulently convective core of Beta Cephei variables is suggested, which causes periodic mixing of hydrogen into the otherwise depleted core. The extra pressure at the mixing shell, due to the newly added hydrogen gives periodic pushes on the envelope and the pulsations grow. For the specific model, 2 Virginis is used, having well-known mass, radius and luminosity. The recent stopping of the pulsations of this star may indicate that the proposed overshooting growth of the convective core may be temporarily terminated. (GHT)

Optical pumping of hot LO phonons in GaAs has been studied as a function of the excitation photon frequency. The experimental results are in good agreement with a model calculation which includes both inter- and intra-valley electron-phonon scatterings. The GAMMA-L and GAMMA-X intervalley electron-phonon interactions in GaAs have been estimated.

We have produced a series of reactor designs to meet the variety of driver-target combinations that could possibly result from the inertial-confinement fusion program. In this paper we discuss four reactor designs, the goals of which are low cost; a low probability of risk to the public, the plant employees, and the utility investment; and a minimal environmental impact under normal plant operation. HYLIFE is a low pulse rate, lithium-cooled reactor. Pulse*Star and Cascade are high pulse rate reactors. In Pulse*Star, fusion energy is absorbed in the PbLi pool; in Cascade it is absorbed by Li/sub 2/O particles. Sunburst, a very low pulse rate, lithium-cooled reactor, directly converts over 40% of the fusion energy to electricity using a pulsed magnetic field.

The new radiation dose estimates for Hiroshima and Nagasaki are here combined with epidemiologic data from the A-bomb survivors and examined radiobiologically for compatability with other human and experimental data. The new doses show certain improvements over the original T65 doses. However, they suggest for chronic granulocytic leukemia, total malignancies, and chromosome aberrations, at neutron doses of 1 rad, RBEs in excess of 100, higher than expected from other findings. This and other indications suggest that either there are unrecognized systematic problems with the various radiobiological data, or the new doses are deficient in neutrons for Hiroshima, by a factor of about five. If in fact there were actually some 5-fold more dose from neutrons at Hiroshima than estimated by the new calculations, the RBEs would agree well with laboratory results, and other inconsistencies would largely disappear. Cancer risks are estimated for neutrons from the new doses and are compared with those estimated from radiobiologically reconciled doses (the new doses adjusted by adding approximately 5-fold more neutrons). The latter estimates appear more reasonable. For low-LET radiation, cancer risk estimates are altered very little by the new dose estimates for Nagasaki.