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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Fermi surface topology effects on Nernst- Ettingshausen coefficient from measurements in magnetic fields to 3.3 tesla and 1.2-4.2 K temperatures in metallic tin
Thermodynamic approach to equation of state of magnetized Fermi gas, deriving energy eigenvalues of free electron in magnetic field
Fermi surface data of alkali metals interpreted in terms of interaction between conduction electrons and ionic lattice for deducing partial wave phase shifts
Field ionization at metal surfaces as rearrangement collision, considering anisotropic electron tunneling probabilities produced by Fermi surface
Dielectric response of semiinfinite metal surface to external point charge in linearized Fermi- Thomas approximation, discussing potential in metal and vacuum
Thomas-Fermi approximation applied to calculation of equations of state and thermodynamic functions at high pressure from differential equations of statistical atom model
Statistical electron density distributions and Thomas-Fermi-Dirac screening functions for positive ions with various ionization degrees
Ferromagnetic Ni band structure and Fermi surface including spin-orbit and exchange interactions obtained by Mueller interpolation scheme
Single crystal and pyrolytic graphite, examining spin split Landau levels, Fermi energy changes and anomalous g shifts
Tungsten crystal Fermi surface galvanomagnetic coefficients in scattering process by semiempirical scheme
Impurity lifetime broadening due to scattering at Fermi surfaces, calculating Dingle temperature in noble metals
The problem of a noninteracting Fermi gas in a finite square-well potential is solved analytically in the limit that the well becomes infinitely wide. The errors of previous authors using this model as a first approximation to the problem of a simple metal with surfaces are pointed out.
Review of a number of nighttime acceleration mechanisms proposed in the literature for the role of producing the keV nighttime auroral-particle fluxes. Parallel electric fields are rejected for several reasons, but particularly because of the observed simultaneous precipitation of electrons and protons. Acceleration in the neutral sheet is inadequate for producing the particle energies, the observed field-aligned pitch-angle distribution at high latitudes, and the spectral hardening toward lower latitudes. Neutral point mechanisms, although often suggested in principle, have never been demonstrated satisfactorily in theory or in practice. Pitch-angle scattering from a trapped population produced by transverse adiabatic compression is also incapable of producing the field-aligned distribution. It is therefore suggested that longitudinal or Fermi acceleration, which results from the known magnetospheric convection, is the main nighttime auroral acceleration mechanism. The argument is supported by data obtained with the soft-particle spectrometer on Isis 1.
We obtain in closed analytic form, estimates for the thermodynamic properties of classical fluids with pair potentials of Yukawa type, with special reference to dense fully ionized plasmas with Thomas-Fermi or Debye-Hueckel screening. We further generalize the hard-sphere perturbative approach used for similarly screened two-component mixtures, and demonstrate phase separation in this simple model of a liquid mixture of metallic helium and hydrogen.
Forced flow of a Fermi liquid is studied for a cell geometry consisting of two planes with a separation on the order of mean free path. An approximate transport equation is used to derive an integral equation for the velocity profile, which is solved numerically. Results for the total flux through the cell, which determines the dissipation, are given as a function of the Knudsen number N (ratio of cell thickness to mean free path). Effects of specular reflection at the boundaries are considered. It is found that the dissipation has a minimum at N approximately equal to 1/2, and behaves linearly for N greater than or equal to 3. Implications for present experimentation are discussed.
A series of measurements of normal state and superconducting properties were made in zero and in high magnetic fields. When these results are combined with a complete set of theoretical expressions, a number of Fermi surface parameters are found.
Forced flow of a Fermi liquid is studied for a cell geometry consisting of two planes with a separation on the order of the mean free path. An approximate transport equation is used to derive an integral equation for the velocity profile, which is solved numerically. Results for the total flux through the cell, which determines the dissipation, are given as a function of the Knudsen number kappa (ratio of cell thickness to mean free path). Effects of specular reflection at the boundaries are considered. It is found that the dissipation has a minimum at kappa of 1/2, and behaves linearly for kappa not less than 3. Implications for present experimentation are discussed.
The effects of boundary surface fluctuations on a spectrum of electromagnetic radiation trapped in a high Q (quality) cavity are considered. Undulating walls introduce small frequency shifts at reflection to the radiation, and it is argued that the process is entirely analogous to both Fermi (particle) acceleration and inverse Compton scattering. A Fokker-Planck formalism is pursued; it yields a diffusion equation in frequency for which the Green's function and steady-state solutions are found. Applying this analysis to the Jovian continuum radiation discovered by Voyager spacecraft, it is suggested that characteristic diffusion times are greater than 1 year, and that in order to account for the steep frequency spectra observed, an unidentified loss mechanism must operate in the cavity with a decay time constant approximately equal to the characteristic diffusion time divided by 28. A radiator-reactor model of the cavity is investigated to provide an estimate for the intrinsic luminosity of the low frequency (approximately 100 Hz) continuum source whose power is approximately 7 x 10 to the 6th W.