Inhomogeneous two-stream instability.
Two oppositely charged particle beams interaction instability in cold plasma, discussing stabilization by periodic electrostatic potential
Knorr, G.↗
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Flux and speed distributions of molecular beams after scattering by metal surfaces.
Argon and nitrogen molecular beams particle flux and velocity distributions after scattering from polycrystalline Ni and stainless steel surfaces
Fisher, S. S.↗
Mean life measurements using the beam foil light source.
Mean life measurement of excited ions electronic levels using beam foil light source, emphasizing beam particle monitoring and theoretical equations
Bickel, W. S.↗
Cross section for C12/alpha, alpha n/C11 at 920 MeV
High energy alpha particle beam exposed to plastic scintillators, determining spallation cross section for C12/alpha, alpha n/C11
Radin, J.↗
A mathematical model of the arc Pioneer 6/7 plasma probe
Mathematical model of arc Pioneer 6/7 plasma probe electrostatic analyzer responding to monoenergetic unidirectional charged particle beam
Day, J. R.↗
Scattering of 42-MeV alpha particles from Cu-65
The extended particle-core coupling model was used to predict the properties of low-lying levels of Cu-65. A 42-MeV alpha particle cyclotron beam was used for the experiment. The experiment included magnetic analysis of the incident beam and particle detection by lithium-drifted silicon semiconductors. Angular distributions were measured for 10 to 50 degrees in the center of mass system. Data was reduced by fitting the peaks with a skewed Gaussian function using a least squares computer program with a linear background search. The energy calibration of each system was done by pulsar, and the excitation energies are accurate to + or - 25 keV. The simple weak coupling model cannot account for the experimentally observed quantities of the low-lying levels of Cu-65. The extended particle-core calculation showed that the coupling is not weak and that considerable configuration mixing of the low-lying states results.
Stewart, W. M.↗
Quantized vortices around wavefront nodes, 2
Quantized vortices can occur around nodal points in wavefunctions. The derivation depends only on the wavefunction being single valued, continuous, and having continuous first derivatives. Since the derivation does not depend upon the dynamical equations, the quantized vortices are expected to occur for many types of waves such as electromagnetic and acoustic. Such vortices have appeared in the calculations of the H + H2 molecular collisions and play a role in the chemical kinetics. In a companion paper, it is shown that quantized vortices occur when optical waves are internally reflected from the face of a prism or particle beams are reflected from potential energy barriers.
Hirschfelder, J. O.↗
A multiwire proportional counter system for high energy astrophysics
Resolution tests of multiwire proportional counter delay line readout systems are reported. The system is being developed at NASA/JSC for use in a large balloon borne magnet spectrometer. The system is ultimately intended for use in Space Shuttle missions. Tests of two different types of delay line and associated electronics carried out in minimum ionizing particle beams (accelerator and sea level cosmic ray) are reported. Resolution performance is shown to be strongly dependent on type of gas mixture and in the case of inclined events upon the propagation velocity of the delay line. The resolution performance achieved for magic gas chamber filling (100 um at normal incidence) is far superior to any other state of the art technique capable of being applied to large geometry factor systems.
Lacy, J. L.↗
Measurements on the development of cascades in a tungsten-scintillator ionization spectrometer
The response of a tungsten-scintillator ionization spectrometer to accelerated particle beams has been investigated. Results obtained from exposure of the approx. 1000 g/sq cm apparatus to 5, 10, and 15 GeV/c electrons and pions as well as to 2.1 GeV/nucleon C-12 and O-16 ions are presented. These results include cascade-development curves, fractions of the primary energy measured by the spectrometer, and resolutions of the apparatus for measuring the primary energies. For 15 GeV/c electrons, an average of about 82% of the incident energy is measured by the apparatus with resolution (normal standard deviation) of about 6%. For 15 GeV/c pions, an average of about 65% of the incident energy is measured with resolution of about 18%. The energy resolution improves with increasing energy and with increasing depth of the spectrometer.
Cheshire, D. L.↗
Magnetospheric Physics
Dynamic phenomena associated with the plasmasphere, and energy and momentum transferred from the solar wind to the upper atmosphere by means of magnetic field-aligned currents are discussed. Both the LEO and GEO space stations offer potential opportunities to probe the detailed electrical structure of the space plasmas, particle beam atmospheric penetration, beam drifts in the presence of perpendicular electric fields, and permit to study multi-echo dynamics.
Source record↗
Determination of oxygen in silicon and carbide by activation with 27.2 meV alpha particles
The Si sample was polished on one side, and on the other side Ni was applied chemically and soldered with Pb to a water cooled Cu substrate. Optical quartz standard was fixed from the other side. Si carbide samples were soldered to a substrated with In. The prepared samples were irradiated in a cyclotron with a 27.2 MeV alpha particle beam. The layers were removed from the Si and Si carbide samples by grinding and the positron activity of F-18(t sub 1/2 110 min) was measured by using a gamma, gamma coincidence spectrometer with two NaI(TI) crystals. For analysis of Si carbide, the activity decay curve of the samples was recorded to find the contribution of the positron activity of Cu-65(t sub 1/2 12.9 hr) which formed from Ni impurity on irradiation.
Dolgolenko, A. P.↗
Evidence for two-dimensional inertial turbulence in a cosmic-scale low-beta plasma
Magnetospheric electric-field power spectral densities measured from high-altitude balloons and the Hawkeye 1 satellite are combined in wavenumber space and exhibit a power-law spectrum with index -1.6 + or -0.3 below a wavenumber of 0.05 reciprocal km and index -2.8 + or -0.3 above 2 reciprocal km. This spectrum agrees with that predicted for the inertial subrange of an isotropic homogeneous two-dimensional fluid and for a two-dimensional plasma when energy enters the system at the spectral knee and there exists a viscous dissipation mechanism at large wavenumbers. The wavelength of the spectral knee corresponds to that of folds and curls in the aurora and may be due to an instability of the auroral particle beams.
Kelley, M. C.↗
LSST system analysis and integration task for an advanced science and application space platform
To support the development of an advanced science and application space platform (ASASP) requirements of a representative set of payloads requiring large separation distances selected from the Science and Applications Space Platform data base. These payloads were a 100 meter diameter atmospheric gravity wave antenna, a 100 meter by 100 meter particle beam injection experiment, a 2 meter diameter, 18 meter long astrometric telescope, and a 15 meter diameter, 35 meter long large ambient deployable IR telescope. A low earth orbit at 500 km altitude and 56 deg inclination was selected as being the best compromise for meeting payload requirements. Platform subsystems were defined which would support the payload requirements and a physical platform concept was developed. Structural system requirements which included utilities accommodation, interface requirements, and platform strength and stiffness requirements were developed. An attitude control system concept was also described. The resultant ASASP concept was analyzed and technological developments deemed necessary in the area of large space systems were recommended.
Source record↗
Magnetospheric multiprobes: Investigations and instrumentation
The multiprobe scientific objectives are to: (1) determine the spatial structure of plasma phenomena such as the aurora, convection reversals, and ion troughs; (2) separate spatial and temporal variations in these phenomena; (3) determine field aligned current densities; (4) perform multiple point analysis of particle beams, wave fields, and plasma clouds that are injected into the ionosphere and magnetosphere by Spacelab active experiment facilities. Trade studies described include: instrument accommodations, power, attitude determination, electric field antennas, storage and ejection, thermal control, tracking communications, command and data management, payload and mission specialist support, functional objectives, and orbital analysis.
Burch, J. L.↗
Vacuum applications of metal foams
Several vacuum applications of copper foams in the density range 2-5% and pore sizes of 0.5-0.7 mm are discussed, such as a foreline hydrocarbon trap in a mechanical vacuum pump, a molecular-flow resistor, a diffuser, and a water injector. Other suggested applications include the use of foam copper in the form of an externally heated plug to remove traces of oxygen from inert gases bled into a vacuum system through a stainless steel line and the use of the porous surface for minimizing release of secondary electrons from electrodes in the path of charged particle beams.
Kendall, B. R. F.↗
Particle acceleration at planetary bow shock waves
One property of the collisionless shocks that may be studied through a comparison of their behavior in a variety of plasma conditions at several different planets is the occurrence of MHD waves, associated with particle beams accelerated at these shocks and flowing backward to the sun. Mercury, Venus, earth and Jupiter observations of one of these wave classes show that (1) the empirical relationship between interplanetary field strength and wave frequency in the observer's rest frame is approximately true at all the planets considered, and (2) the observed frequencies are consistent with resonance with beams of ions of the same energy at each of the planets. This is, in turn, in keeping with the Sonnerup (1969) geometrical model of ion reflection at collisionless shocks. It is suggested that this ion acceleration mechanism may occur in astrophysical systems similar to the solar system, providing a source of acceleration for cosmic rays.
Hoppe, M. M.↗
Spacelab-1: An early space station for science and technology
The scientific capabilities of the Spacelab manned pallet are reviewed, together with the implications of an expansion of the research effectiveness with a free-flying platform. The premier Spacelab flight will carry out earth observations with a metric camera and SAR, atmospheric studies will be performed with imaging spectrometers, and space plasma physics will be examined by injecting particle beams or VLF waves into the near-Shuttle environment. Radiance and spectrum data will be gathered of the sun and UV and X ray information will be recorded from the stars. Experimentation will also be carried out for on-board crystal growth, metallurgy, and glassy material production, as well as the response of biological systems to zero-g conditions and hard space radiation. The telemetry, time, crewmember participation, and on-board controls required for Spacelab operations are outlined. Missions for a space platform for studying the atmosphere/space interface are described.
Knott, K.↗
Reflective Shields for Artificial Satellites
Report proposes reflective shield that protects spacecraft from radiant energy. Also gives some protection against particle beams and cosmic rays. Conceptual shield essentially advanced version of decorative multifaceted mirror balls often hung over dance floors. Mirror facets disperse radiant energy in many directions.
Bouquet, F. L.↗