Plasma diagnostics package. Volume 1: OSS-1 section

This volume (1) of the Plasma Diagnostics Package (PDP) final science report contains a summary of all of the data reduction and scientific analyses which were performed using PDP data obtained on STS-3 as a part of the Office of Space Science first payload (OSS-1). This work was performed during the period of launch, March 22, l982, through June 30, l983. During this period the primary data reduction effort consisted of processing summary plots of the data received by the 14 instruments located on the PDP and submitting these data to the National Space Science Data Center (NSSDC). The scientific analyses during the performance period consisted of general studies which incorporated the results of several of the PDP's instruments, detailed studies which concentrated on data from only one or two of the instruments, and joint studies of beam-plasma interactions with the OSS-1 Fast Pulse Electron Generator (FPEG) of the Vehicle Charging and Potential Investigation (VCAP). Internal reports, published papers and oral presentations which involve PDP/OSS-1 data are listed in Sections 3 and 4. A PDP/OSS-1 scientific results meeting was held at the University of Iowa on April 19-20, 1983. This meeting was attended by most of the PDP and VCAP investigators and provided a forum for discussing and comparing the various results, particularly with regard to the shuttle orbiter environment. One of the most important functional objectives of the PDP on OSS-1 was to characterize the orbiter environment

Plasma diagnostics package. Volume 2: Spacelab 2 section. Part B: Thesis projects

This volume (2), which consists of two parts (A and B), of the Plasma Diagnostics Package (PDP) Final Science Report contains a summary of all of the data reduction and scientific analyses which were performed using PDP data obtained on STS-51F as a part of the Spacelab 2 (SL-2) payload. This work was performed during the period of launch, July 29, 1985, through June 30, 1988. During this period the primary data reduction effort consisted of processing summary plots of the data received by 12 of the 14 instruments located on the PDP and submitting these data to the National Space Science Data Center (NSSDC). Three Master's and three Ph.D. theses were written using PDP instrumentation data. These theses are listed in Volume 2, Part B

Suprathermal plasma observed on STS-3 Mission by plasma diagnostics package

Artificially produced electron beams were used extensively during the past decade as a means of probing the magnetosphere, and more recently as a means of actively controlling spacecraft potential. Experimentation in these areas has proven valuable, yet at times confusing, due to the interaction of the electron beam with the ambient plasma. The OSS-1/STS-3 Mission in March 1982 provided a unique opportunity to study beam-plasma interactions at an altitude of 240 km. On board for this mission was a Fast Pulse Electron Generator (FPEG). Measurements made by the Plasma Diagnostics Package (PDP) while extended on the Orbiter RMS show modifications of the ion and electron energy distributions during electron beam injection. Observations made by charged particle detectors are discussed and related to measurements of Orbiter potential. Several of the PDP instruments, the joint PDP/FPEG experiment, and observations made during electron beam injection are described

Advanced nickel-cadmium batteries for geosynchronous spacecraft

A nickel cadmium battery was developed that can be operated at 80 percent depth of discharge in excess of 10 years in a geosynchronous orbit application, and has about a 30 percent weight savings per spacecraft over present nickel cadmium batteries when used with a 1000 watts eclipse load. The approach used in the development was to replace nylon separators with inert polymer impregnated zirconia, use electrochemically deposited plates in place of conventional chemically precipitated ones, and use an additive to extend negative plate lifetime. The design has undergone extensive testing using both engineering and protoflight cell configurations

Pressure-Induced Simultaneous Metal-Insulator and Structural-Phase Transitions in LiH: a Quasiparticle Study

A pressure-induced simultaneous metal-insulator transition (MIT) and structural-phase transformation in lithium hydride with about 1% volume collapse has been predicted by means of the local density approximation (LDA) in conjunction with an all-electron GW approximation method. The LDA wrongly predicts that the MIT occurs before the structural phase transition. As a byproduct, it is shown that only the use of the generalized-gradient approximation together with the zero-point vibration produces an equilibrium lattice parameter, bulk modulus, and an equation of state that are in excellent agreement with experimental results.Comment: 7 pages, 4 figures, submitted to Europhysics Letter

Anxious to see you: Neuroendocrine mechanisms of social vigilance and anxiety during adolescence.

Social vigilance is a behavioral strategy commonly used in adverse or changing social environments. In animals, a combination of avoidance and vigilance allows an individual to evade potentially dangerous confrontations while monitoring the social environment to identify favorable changes. However, prolonged use of this behavioral strategy in humans is associated with increased risk of anxiety disorders, a major burden for human health. Elucidating the mechanisms of social vigilance in animals could provide important clues for new treatment strategies for social anxiety. Importantly, during adolescence the prevalence of social anxiety increases significantly. We hypothesize that many of the actions typically characterized as anxiety behaviors begin to emerge during this time as strategies for navigating more complex social structures. Here, we consider how the social environment and the pubertal transition shape neural circuits that modulate social vigilance, focusing on the bed nucleus of the stria terminalis and prefrontal cortex. The emergence of gonadal hormone secretion during adolescence has important effects on the function and structure of these circuits, and may play a role in the emergence of a notable sex difference in anxiety rates across adolescence. However, the significance of these changes in the context of anxiety is still uncertain, as not enough studies are sufficiently powered to evaluate sex as a biological variable. We conclude that greater integration between human and animal models will aid the development of more effective strategies for treating social anxiety

Visualizing Pure Quantum Turbulence in Superfluid 3^{3}He: Andreev Reflection and its Spectral Properties

Superfluid $^3$He-B in the zero-temperature limit offers a unique means of studying quantum turbulence by the Andreev reflection of quasiparticle excitations by the vortex flow fields. We validate the experimental visualization of turbulence in $^3$He-B by showing the relation between the vortex-line density and the Andreev reflectance of the vortex tangle in the first simulations of the Andreev reflectance by a realistic 3D vortex tangle, and comparing the results with the first experimental measurements able to probe quantum turbulence on length scales smaller than the inter-vortex separation.Comment: 5 pages, 4 figures, and Supplemental Material (2 pages, 2 figures

Fermi surface of the colossal magnetoresistance perovskite La_{0.7}Sr_{0.3}MnO_{3}

Materials that exhibit colossal magnetoresistance (CMR) are currently the focus of an intense research effort, driven by the technological applications that their sensitivity lends them to. Using the angular correlation of photons from electron-positron annihilation, we present a first glimpse of the Fermi surface of a material that exhibits CMR, supported by ``virtual crystal'' electronic structure calculations. The Fermi surface is shown to be sufficiently cubic in nature that it is likely to support nesting.Comment: 5 pages, 5 PS figure

Multipoint investigation of the source region of storm-time chorus

International audienceIn this case study we investigate the source region of whistler-mode chorus located close to the geomagnetic equator at a radial distance of 4.4 Earth radii. We use measurements from the four Cluster spacecraft at separations of less than a few hundreds of km, recorded during the geomagnetic storm of 18 April 2002. The waveforms of the electric field fluctuations were obtained by the WBD instruments in the frequency range 50Hz-9.5kHz. Using these data, we calculate linear and rank correlation coefficients of the frequency averaged power-spectral density measured by the different spacecraft. Those coefficients have been recently shown to decrease with spacecraft separation distance perpendicular to the static magnetic field cchor03 with a characteristic scale length of 100km. We find this characteristic scale varying between 60 and 200km for different data intervals inside the source region. We examine possible explanations for the observed large scatter of the correlation coefficients, and we suggest a simultaneously acting effect of random positions of locations at which the individual chorus wave packets are generated. The statistical properties of the observations are approximately reproduced by a simple 2-D model of the source region, assuming a perpendicular half-width of 35km (approximately one wavelength of the whistler-mode waves) for the distribution of power radiated from individual active areas