No description available.

No description available.

Thesis (Ph. D.)--University of Hong Kong, 1976. / Also available in print.

Academish proefschrift--Amsterdam. / Bibliography: p. 103-104.

Thesis (Ph. D.)--University of Chicago, Dept. of Physics, March 2000. / Includes bibliographical references. Also available on the Internet.

Aluminum-26 (26Al) is a radioactive isotope that has a relatively short half-life, approximately 0.74 million yeras. Thus, since the formation of the earth some 4500 million years ago, the concentrations of 26Al should have decayed to nearly zero, yet 26Al has also been found in lunar and Martian samples. We attempt to elucidate the mechanism by which this aluminum arrived, or formed, on/in the space blanket, the lunar material, and the Martian material. The fecundity of four proposed abundance schemes is analyzed. The four schemes are as follows: (I) stellar evolution and nucleosynthesis, (ii) nuclear testing in the upper atmosphere, (iii) fission powered satellites, and (iv) cosmic ray-induced nuclear reactions.

A cosmic ray magnetic particle spectrometer utilizing wire spark chambers and a superconducting magnet for momentum determination and scintillators for charge and velocity determination has been operated on top of Mt. Lemmon near Tucson, Arizona at an atmospheric depth of 747 g/cm². Twenty weeks of data were taken and the proton energy spectrum in the momentum range of 0.6 to 2.4 GeV/c has been determined. Antiproton events were observed and a p/p ratio of 1.5(+1.85,-0.95) x 10⁻³ at a momentum of 1.05 GeV/c was measured. Deuteron intensities and alpha particle upper limits for this energy region are also presented.

Call number: LD2668 .T4 1966 G618 / Master of Science

I begin this study by presenting an overview of the theory of magnetohydrodynamics and the necessary conditions to justify the fluid treatment of a plasma. Upon establishing the fluid description of a plasma we move on to a discussion of magnetohydrodynamics in both the ideal and Hall regimes. This framework is then extended to include multiple plasmas in order to consider two problems of interest in the field of theoretical space physics. The first is a study on the evolution of a partially ionized plasma, a topic with many applications in space physics. A multi-fluid approach is necessary in this case to account for the motions of an ion fluid, electron fluid and neutral atom fluid; all of which are coupled to one another by collisions and/or electromagnetic forces. The results of this study have direct application towards an open question concerning the cascade of Kolmogorov-like turbulence in the interstellar plasma which we will discuss below. The second application of multi-fluid magnetohydrodynamics that we consider in this thesis concerns the amplification of magnetic field upstream of a collisionless, parallel shock. The relevant fluids here are the ions and electrons comprising the interstellar plasma and the galactic cosmic ray ions. Previous works predict that the streaming of cosmic rays lead to an instability resulting in significant amplification of the interstellar magnetic field at supernova blastwaves. This prediction is routinely invoked to explain the acceleration of galactic cosmic rays up to energies of 10¹⁵ eV. I will examine this phenomenon in detail using the multi-fluid framework outlined below. The purpose of this work is to first confirm the existence of an instability using a purely fluid approach with no additional approximations. If confirmed, I will determine the necessary conditions for it to operate.

published_or_final_version / Physics / Master / Master of Science