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Full-Text Articles in Physics
Ultrafast Phenomena: A Laboratory Experiment For Undergraduates, T. D. Donnelly, Carl H. Grossman
Ultrafast Phenomena: A Laboratory Experiment For Undergraduates, T. D. Donnelly, Carl H. Grossman
Physics & Astronomy Faculty Works
We present a set of experiments that introduce students to ultrafast science. We discuss the relationship between the description of an ultrashort laser pulse in the frequency domain and the time domain. Using experimental results we demonstrate that this relationship is constrained by the lower limit of the Heisenberg uncertainty principle. Students carrying out the experiments will become familiar with ultrafast techniques, such as autocorrelation and laser cavity design, as well as various other concepts such as dispersion, Fourier transformation, interference, and nonlinear optics. (C) 1998 American Association of Physics Teachers.
Experimental Observation Of Correlated Magnetic Reconnection And Alfvénic Ion Jets, Thomas W. Kornack , '98, Peter K. Sollins , '98, Michael R. Brown
Experimental Observation Of Correlated Magnetic Reconnection And Alfvénic Ion Jets, Thomas W. Kornack , '98, Peter K. Sollins , '98, Michael R. Brown
Physics & Astronomy Faculty Works
Correlations between magnetic reconnection and energetic ion flow events have been measured with merging force free spheromaks at the Swarthmore Spheromak Experiment. The reconnection layer is measured with a linear probe array and ion flow is directly measured with a retarding grid energy analyzer. Flow has been measured both in the plane of the reconnection layer and out of the plane. The most energetic events occur in the reconnection plane immediately after formation as the spheromaks dynamically merge. The outflow velocity is nearly Alfvenic. As the spheromaks form equilibria and decay, the flow is substantially reduced.
Scaling Studies Of Spheromak Formation And Equilibrium, Cameron G. R. Geddes , '97, Thomas W. Kornack , '98, Michael R. Brown
Scaling Studies Of Spheromak Formation And Equilibrium, Cameron G. R. Geddes , '97, Thomas W. Kornack , '98, Michael R. Brown
Physics & Astronomy Faculty Works
Formation and equilibrium studies have been performed on the Swarthmore Spheromak Experiment (SSX). Spheromaks are formed with a magnetized coaxial plasma gun and equilibrium is established in both small (d(small)=0.16 m) and large (d(large)=3d(small)=0.50 m) copper flux conservers. Using magnetic probe arrays it has been verified that spheromak formation is governed solely by gun physics (in particular the ratio of gun current to flux, mu(0)I(gun)/Phi(gun)) and is independent of the flux conserver dimensions. It has also been verified that equilibrium is well described by the force free condition del xB=lambda B (lambda=constant), particularly early in decay. Departures from the force-free …
Nature Of The Blue-Phase-Iii-Isotropic Critical Point: An Analogy With The Liquid-Gas Transition, M. A. Anisimov, V. A. Agayan, Peter J. Collings
Nature Of The Blue-Phase-Iii-Isotropic Critical Point: An Analogy With The Liquid-Gas Transition, M. A. Anisimov, V. A. Agayan, Peter J. Collings
Physics & Astronomy Faculty Works
The analogy with the liquid-gas critical point is analyzed to clarify the nature of the pretransitional behavior of physical properties in the vicinity of the Blue-Phase-m-isotropic transition in chiral liquid crystalline systems. The analogy is unusual: temperature serves as the ordering field and entropy plays the role of the order parameter. Both mean field and parametric equations of state are formulated in terms of scaling fields. The scaling fields are linear combinations of the physical fields, which are temperature and chirality. It is shown that mixing of the physical field variables naturally leads to a strong asymmetry with respect to …