Physical Sciences and Mathematics Commons^™

Equatorial F-Region Zonal Plasma Drifts, Bela G. Fejer, E. Kudeki, D. T. Farley

Bela G. Fejer

We have examined in detail the F region plasma drifts measured at Jicamarca, Peru, during 1978–1981, a period of high solar activity, and compared these drifts with Jicamarca data taken during periods of lower activity, as well as with other equatorial zonal neutral wind and plasma drift measurements. The increase in solar activity causes larger nighttime eastward plasma drifts at Jicamarca and delays the morning reversal time from eastward nighttime to westward daytime drifts. The radar data seem to be in good agreement with nighttime neutral wind measurements made by the DE-2 satellite, but are systematically smaller than spaced receiver …

Quantum Electrodynamics At Finite Temperature, Jf Donoghue, Br Holstein, Rw Robinett

Barry R Holstein

We present a systematic examination of finite temperature effects in quantum electrodynamics at one loop order. We calculate mass, charge, and wavefunction renormalization, demonstrate the running of the coupling constant at high temperatures, and study the renormalized vertex function and the energy momentum tensor. The confusion in the literature concerning the finite temperature corrections to the electron's magnetic moment is resolved. We also present the finite temperature effects in scalar electrodynamics. Throughout we stress the need to provide a well-defined method to observe a given quantity when interpreting the results of a calculation, and we suggest new techniques which incorporate …

Spectral Properties Of Percolating Central Force Elastic Networks, Anthony Day, R. Tremblay, A.-M. Tremblay

Anthony Roy Day

The exponent describing the low frequency spectrum of vibrations for the central force universality class is computed with both the Coherent Potential Approximation and numerical simulations. The results of both calculations agree surprisingly well.

Reanalysis Of Higgs-Boson-Exchange Models Of Cp Violation, Jf Donoghue, Br Holstein

Barry R Holstein

We reexamine the value of ɛ'/ɛ in models where CP violation is due to the exchange of charged Higgs bosons. Previous work has been flawed by incorrect treatment of the chiral properties of weak amplitudes. We use the effective-chiral-Lagrangian framework to clear up these aspects. The resultant value of ɛ'/ɛ is estimated to be in the neighborhood of ɛ'/ɛ=-0.006, although this estimate could be off by a factor of two or three in either direction. This value is consistent with the present experimental bounds.

Interaction Of The Zonalwinds With The Equatorial Midnight Pressure Bulge In The Earth's Thermosphere: Empiricalevidence Of Momentum Balance, F. A. Herrero, H. G. Mayr, N. W. Spencer, A. E. Hedin, Bela G. Fejer

Bela G. Fejer

A minimum is observed at midnight in the time variation of averaged zonal winds measured in-situ near the equator at an average altitude of about 350 km, and we inquire whether observations of the equatorial midnight pressure bulge are consistent with this feature. The observed zonal wind maintains an eastward direction all night. It increases steadily in the early evening reaching a maximum of about 160 m/s at 2100 hrs local time (LT), dropping to a minimum of about 70 m/s around 2400 LT, then up to about 120 m/s around 0300 LT, decreasing thereafter and turning westward in the …

Behavior Of An Electron In Helium Gas, John Bartholomew, Randall W. Hall, Bruce J. Berne

Randall W. Hall

N-Color Spin Models In The Large N Limit, Mehran Kardar, Miron Kaufman

Miron Kaufman

N color spin models are introduced and examined in the large N limit. The free energy and critical properties at the phase transition are studied. With relevant couplings between colors the transition becomes either first order or Fisher renormalized. With irrelevant couplings there is a crossover to first-order transitions through a nonclassical tricritical point. Connections are established between the N-color model, compressible systems, and systems with random impurities.

Determining The Temperature-Dependent Characteristic Temperature Of Beryllium From Electrical Resistance Measurements, Thomas W. Listerman, Xiao-Li Zhou

Thomas Listerman

We have developed an intermediate-level laboratory experiment to determine the temperature- dependent characteristic temperature of beryllium. The apparatus used to measure the resistance of a beryllium wire sample between liquid nitrogen and room temperatures was simple. The characteristic temperatures obtained from these data using the Block-Grüneisen model are in reasonable agreement with literature values obtained from resistivity and heat capacity experiments. The experiment introduced students to cryogenic and computer data analysis techniques and forced them to extend their knowledge of the theory of electrical resistance and of characteristic temperatures.

Random-Field Critical Behavior And The Ginzburg Criterion, Miron Kaufman, Mehran Kardar

Miron Kaufman

The Ginzburg criterion for crossover from classical to nonclassical critical behavior is derived in the presence of random fields. Experiments on dilute antiferromagnets in a field are examined, and the possibility of such a crossover is investigated. We also point out that the (necessarily) symmetric logarithmic divergence observed in birefringence measurements can be accompanied by a discontinuity, and a fitting form which allows for this and other corrections to scaling is proposed.

Theory Of Spectral Asymmetries And Nonlinear Currentsin The Equatorial Electrojet, E. Kudeki, D. T. Farley, Bela G. Fejer

Bela G. Fejer

The spectral up-down asymmetry of type 1 echoes returned from the equatorial electrojet irregularities is shown to be a consequence of the nonlinear development of the horizontally propagating large scale primary waves which dominate the k spectrum of the electrojet turbulence. The waves reduce the vertical electric polarization field of the electrojet and suffer second harmonic distortion as they grow. These effects together could cause an asymmetry exceeding 20% between the upward and downward components of the relative (to the ions) electron velocity associated with the primary waves. This asymmetry, which changes its direction from day to night as does …

Symmetry Behavior Of The Static Taub Universe: Effect Of Curvature Anisotropy, T. C. Shen, B. L. Hu, D. J. O'Connor

T. -C. Shen

Using the static Taub universe as an example, we study the effect of curvature anisotropy on symmetry breaking of self-interacting scalar field. The one-loop effective potential of a λφ⁴ field with arbitrary coupling (ξ) is computed by ζ-function regularization. It is expressed as a perturbative series in a small anisotropy parameter α measuring the deformation from the spherical Einstein universe with radius of curvature α. This result is used for analyzing the symmetry behavior of such a system as a function of the geometric (α,α) and field (ξ,λ) parameters. The result is also used to address the question of …

Gravitational Twins Revisited, Br Holstein

Barry R Holstein

No abstract provided.

Possible Weak Interaction Experiments With Polarized He-3, Br Holstein

Barry R Holstein

No abstract provided.

Forced Harmonic-Oscillator - A Path Integral Approach, Br Holstein

Barry R Holstein

The problem of the harmonic oscillator driven by an external force is explored using path integral techniques. The qualitative features of the solution are demonstrated.

Semileptonic Hyperon Decay - A Problem For Chiral Perturbation-Theory, Jf Donoghue, Br Holstein

Barry R Holstein

We study the recently computed mk2lnm2k corrections to hyperton beta decay found in chiral perturbation theory. The inclusion of these effects is not compatible with the high precision hyperon data, yielding a fit much inferior to the standard assumption of SU(3) invariance. This incompatibility of data and theory is a problem for the application of chiral perturbation theory.

Viscosity Measurements In Dilute Helium-3-Helium-4 Mixtures, George Schmiedeshoff

George Schmiedeshoff

We have measured the viscosity of a dilute mixture of 3He in 4He at temperatures from 5 to 100 mK and in magnetic fields of 0.35, 2.01 and 8.76 T using a vibrating wire viscometer. Subject to our choice of calibration function, the data at 0.35 T is in good agreement with theory. Due to an interaction of our viscometer with the magnetic field the motion of the wire at 2.01 and 8.76 T is not understood; however, the 2.01 T data can be brought into agreement with the 0.35 T data by adjusting a geometrical constant. An increase in …