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Physics

William & Mary

Theses/Dissertations

1983

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Catastrophes In The Elmo Bumpy Torus, Alkesh R. Punjabi Jan 1983

Catastrophes In The Elmo Bumpy Torus, Alkesh R. Punjabi

Dissertations, Theses, and Masters Projects

Experimentally it is observed that the plasma in Elmo Bumpy Torus (EBT) shows discontinuous changes in the electron line density, electron and ion temperatures and fluctuation levels as the ambient gas pressure or electron cyclotron heating is varied continuously. We use the Point Model of Hedrick et al. for the toroidal core plasma in EBT. The Point Model is not a gradient dynamic system. Hence the Elementary Catastrophe Theory is not directly applicable to the Point Model. Nonetheless, the Point Model equilibria will be shown to exhibit properties which are quite akin to the canonical cusp catastrophe. The ambipolar electric …


A General Theory Of Electron Detachment In Negative Ion Collisions, Tzuu-Shin Wang Jan 1983

A General Theory Of Electron Detachment In Negative Ion Collisions, Tzuu-Shin Wang

Dissertations, Theses, and Masters Projects

In this thesis a general theory of electron detachment in slow collisions of negative ions with atoms is presented. The theory is based upon a semiclassical close-coupling framework, following the work of Taylor and Delos. The Schrodinger equation is reduced, under certain assumptions, to a non-denumerably infinite set of coupled equations. We develop a new method for solving these equations that is more general than the methods used by Taylor and Delos. A zero-order approximation of our solution is applied to the case of H('-)(D('-)) on Ne collisions, the results are compared with the experimental data, and we find good …


Long-Time States Of Inverse Cascades In The Presence Of A Maximum Length Scale, Murshed Hossain Jan 1983

Long-Time States Of Inverse Cascades In The Presence Of A Maximum Length Scale, Murshed Hossain

Dissertations, Theses, and Masters Projects

It is shown numerically, both for the two-dimensional Navier-Stokes equations and for two-dimensional magnetohydrodynamics, that the long-time asymptotic state in a forced inverse-cascade situation is one in which the spectrum is completely dominated by its own fundamental. The growth continues until the fundamental is dissipatively limited by its own dissipation rate. An algebraic model is proposed for the dynamics of such a final state.


Nmr Study Of Molecular Motions In Two Disordered Organic Solids, Philip L. Kuhns Jan 1983

Nmr Study Of Molecular Motions In Two Disordered Organic Solids, Philip L. Kuhns

Dissertations, Theses, and Masters Projects

The molecular motions are studies in two disordered materials that undergo glass transitions. Glycerol is a conventional glass former and cyclohexanol is an orientational glass former.;The technique used in the glycerol experiments was spectral hole burning. Chemical shift anisotropy produces inhomogeneous broadening of NMR lines in orientationally disordered and polycrystalline solids. By saturating or inverting a portion of the anisotropic line, 'burning a hole', molecules of certain orientations are tagged. Subsequent molecular reorientations result in spectral diffusion which is not related to spin-spin interactions. By measuring the broadening and recovery of the hole as a function of time, detailed knowledge …


A Precision Measurement Of The Magnetic Moment Of The Sigma Minus Hyperon, David William Hertzog Jan 1983

A Precision Measurement Of The Magnetic Moment Of The Sigma Minus Hyperon, David William Hertzog

Dissertations, Theses, and Masters Projects

A new measurement of the magnetic moment of the (SIGMA)('-) hyperon has been made and the result is (mu)((SIGMA)('-)) = -1.111 (+OR-) 0.031 (+OR-) 0.011 nuclear magnetons.;Negative kaons from a low-energy separated beam at the Alternating Gradient Synchrotron of the Brookhaven National Laboratory were brought to rest in a novel laminar target consisting of thin metal foils immersed in liquid hydrogen. The production of (SIGMA)('-) hyperons occurred primarily through the reaction K('-)p(--->)(SIGMA)('-)(pi)('+). (SIGMA)('-) hyperon production was tagged by the identification of the energetic (pi)('+). Many of the (SIGMA)('-) so produced stopped in nearby foils of Pb (or W) where …