Thesis--Wisconsin. / Vita. Includes bibliographical references (leaves 197-198).

Using Maxwell's equations of electrodynamics and the linearized fundamental equation of hydrodynamics neglecting all but the ponderomotive force, the two differential equations characterizing toroidal and poloidal modes of oscillations are obtained. Neglecting the coupling between these modes the toroidal mode which appears to be connected with the phenomenon of geomagnetic micropulsations is studied in detail. Substituting for the constant magnetic field the undeformed dipole field of the Earth the eigenperiods of the oscillating lines of force are computed assuming a constant charge density distribution. Using numerical methods the eigenperiods are also obtained in the case of a variable charge density. Since the Earth's dipole field is presumably deformed by the solar wind a compressed dipole field is introduced into the equation of toroidal oscillations. The eigenperiods of the oscillating lines of force are obtained in this case, assuming a constant charge density distribution. For the case of a variable charge density a numerical method is described which could yield the eigenperiods. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

To calculate the emergent radiation field, a realistic atmospheric model and algorithm must be developed. The radiation field may be characterized by the emergent intensities of scattered light. This is possible only if the algorithm determines these intensities as dependent upon atmospheric and angular parameters.

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Call number: LD2668 .T4 1938 W51 / Master of Science

No description available.

Convection in a Boussinesq fluid confined by a annular channel fast rotating about a vertical axis and uniformly heated from below, is one of our concerns in this thesis. An assumption that the channel has a sufficiently large radius in comparison with its gap-width is employed, so that the curvature effect can be neglected. The aspect ratio of the channel has great influence on the convective flow in it. Guided by the result of the linear stability analysis, we perform three-dimensional numerical simulations to investigate the convective flows under three different types of aspect ratios, which are namely the moderate or large aspect ratios, the very small aspect ratios and the moderately small aspect ratios. Also, we numerically study how convection in the channel is affected by inhomogeneous heat fluxes on sidewalls, which is a simple simulation of the thermal interaction between the Earth's core and mantle. Convection and dynamo action in a rapidly rotating, self-gravitating, Boussinesq fluid sphere is the other concern. We develop a finite element model for the dynamo problem in a whole sphere. This model is constructed by incorporating dynamo equations with globally implemented magnetic boundary conditions to a whole sphere convection model, which is also presented here. The coordinate singularity at the center usually encountered when applying the spectral method is no longer an obstacle and no nonphysical assumptions (i.e. hyper-diffusivities) are used in our model. A large effort has been made to efficiently parallelize the model. Consequently, it can take the full advantage of modern massively parallel computers. Based on this dynamo model, we investigate the dynamo process in a sphere and find that self-sustaining dynamos are more difficult to obtain in a sphere than in a spherical shell. They are activated at relatively high Rayleigh numbers. Moreover, the magnetic fields generated are not dipole-dominant, different from those generated in most dynamo simulations.

This investigation is designed to find the net rate of decrease in the component of velocity parallel to the original direction of motion of a proton moving through an electron gas exhibiting a non-spherical velocity distribution.

It is well known that the n-th eigenfunction to one-dimensional Sturm-Liouville eigenvalue problems has exactly n-1 nodes, i.e. non-degenerate zeros. For higher dimensions, it is much more complicated to obtain general statements on the zeros of eigenfunctions. The author states a new conjecture on the number of nodal domains of spherical harmonics, i.e. of connected components of S^2 \ N(u) with the nodal set N(u) = (x in S^2 : u(x) = 0) of the eigenfunction u, and proves it for the first six eigenvalues. It is a sharp upper bound, thus improving known bounds as the Courant nodal domain theorem, see S. Y. Cheng, Comment. Math. Helv. 51, 43-55 (1976; Zbl 334.35022). The proof uses facts on real projective plane algebraic curves (see D. A. Gudkov, Usp. Mat. Nauk 29(4), 3-79, Russian Math. Surveys 29(4), 1-79 (1979; Zbl 316.14018)), because they are the zero sets of homogeneous polynomials, and the spherical harmonics are the restrictions of spherical harmonic homogeneous polynomials in the space to the plane. / Series: Preprint Series / Department of Applied Statistics and Data Processing

Philosophiae Doctor - PhD / The cadmium nuclei have traditionally been regarded as among the best examples of spherical vibrational nuclei. However, advances in nuclear spectroscopy have begun to detail the properties of these nuclei at the two and three vibrational phonon levels, casting doubts on the vibrational assumptions. In particular, the properties of the excited 0+n (for n 2) levels are key to any vibrational model. Excited 0+ states can arise in nuclei in association with the nucleon pairing degrees of freedom, and in model spaces with collective shape degrees of freedom. This thesis reports details of the excited 0+n levels in the even-even nuclei 110;112Cd and 116Sn, and the excited 9 2 + states in 117Sb, investigated using two-proton stripping reactions. The 108;110Pd(3He, n )110;112Cd, 114Cd(3He, n )116Sn and 115In(3He, n )117Sb reactions were investigated using AFRODITE spectrometer in conjunction with a wall of 12 plastic scintillator detectors placed 2 m away from the target chamber.