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Full-Text Articles in Physics
Turbulent Disruptions From The Strauss Equations, Jill Potkalitsky Dahlburg
Turbulent Disruptions From The Strauss Equations, Jill Potkalitsky Dahlburg
Dissertations, Theses, and Masters Projects
The subject of this thesis is an analysis of results from pseudospectral simulation of the Strauss equations of reduced three-dimensional magnetohydrodynamics. We have solved these equations in a rigid cylinder of square cross section, a cylinder with perfectly conducting side walls, and periodic ends. We assume that the uniform-density magnetofluid which fills the cylinder is resistive, but inviscid. Situations which we are considering are in several essential ways similar to a tokamak-like plasma; an external magnetic field is imposed, and the plasma carries a net current which produces a poloidal magnetic field of sufficient strength to induce current disruptions. These …
Stability And Transition Of The Driven Magnetohydrodynamic Sheet Pinch, Russell B. Dahlburg
Stability And Transition Of The Driven Magnetohydrodynamic Sheet Pinch, Russell B. Dahlburg
Dissertations, Theses, and Masters Projects
The stability and transition properties of a bounded, current carrying magnetofluid are explored, using the hydrodynamic theory developed for plane shear flows as a guide. A driven magnetohydrodynamic sheet pinch equilibrium is employed. A sixth order, complex eigenvalue equation which governs the normal modes of small oscillations is derived, and solved numerically by the Chebyshev tau method. Eigenfunctions are shown, as well as the curve of neutral stability. The locus of critical Lundquist numbers has the form of a hyperbola. The nonlinear stability of a primary disturbance of the system is considered. For regions in parameter space close to criticality, …
Fourth Order Mass Splitting In The Bag Model, Timothy John Havens
Fourth Order Mass Splitting In The Bag Model, Timothy John Havens
Dissertations, Theses, and Masters Projects
The fourth order diagrams in the perturbative expansion of the hadron mass are calculated using the static spherical cavity approximation to the MIT bag model and Quantum Chromodynamics (QCD). Only terms with color matrix structure different than that of the second order diagrams are retained.;The fourth order mass splitting is found to be smaller than the second order splitting by a factor of three or more.
First Principles Structure Calculations Using The General Potential Lapw Method, Su-Huai Wei
First Principles Structure Calculations Using The General Potential Lapw Method, Su-Huai Wei
Dissertations, Theses, and Masters Projects
We have developed a completely general first principles self-consistent full-potential linearized-augmented-plane-wave (LAPW) method program within the density functional formalism to calculate electronic band structure, total energy, pressure and other quantities. No symmetry assumptions are used for the crystal structure. Shape unrestricted charge densities and potentials are calculated inside muffin-tin (MT) spheres as well as in the interstitial regions. All contributions to the Hamiltonian matrix elements are completely taken into account. The core states are treated fully relativistically using the spherical part of the potential only. Scalar relativistic effects are included for the band-states, and spin-orbit coupling is included using a …
Combined Translational-Rotational Jumps In Solid (Alpha)-Co And Co(,2), Shang-Bin Liu
Combined Translational-Rotational Jumps In Solid (Alpha)-Co And Co(,2), Shang-Bin Liu
Dissertations, Theses, and Masters Projects
Combined translational-rotational jumps in two orientationally ordered solids, (alpha)-CO and CO(,2), have been measured using C('13) NMR. In the Pa3 structure of these solids, a molecule which jumps to a neighboring (presumably vacant) site will reorient, due to the orientationally ordered structure.;The rates of translation and rotation have been measured independently by using different NMR techniques. The rotations were detected at high field (14.7 MHz) through the modulation of the chemical shift anisotropy; spin echoes and stimulated echoes were used. The translational jumps modulate the dipolar interactions and were studied at low fields (1.256 MHz) with line narrowing and Slichter-Ailion …