38,864 research outputs found
EDUCATIONAL FINANCE IN MINNESOTA: AN EXAMINATION OF THE FOUNDATION AID PROGRAM
Public Economics,
The solar elogation distribution of low frequency radio bursts
Over 500 days of low frequency (less than 5 MHz) radio observations from the IMP-6 spacecraft were accumulated to produce a two dimensional map (frequency versus elongation) of solar type III burst occurrences. This map indicates that most solar bursts are emitted at the second harmonic of the plasma frequency rather than the fundamental. The map also shows that the solar wind electron density varies
Solution of Einstein’s Causality Problem: The AHK Theorem
'Chance' is defined as an event on the time scale withour any cause before it appears. That means, that cause and effect is identical. This is the only way to integrate chance into a consistent theory of causality. The identity of cause and effect is called AHK theorem (Aristotle-Hegel-Kaiser)
Decay dynamics in the coupled-dipole model
Cooperative scattering in cold atoms has gained renewed interest, in
particular in the context of single-photon superradiance, with the recent
experimental observation of super-and subradiance in dilute atomic clouds.
Numerical simulations to support experimental signatures of cooperative
scattering are often limited by the number of dipoles which can be treated,
well below the number of atoms in the experiments. In this paper, we provide
systematic numerical studies aimed at matching the regime of dilute atomic
clouds. We use a scalar coupled-dipole model in the low excitation limit and an
exclusion volume to avoid density-related effects. Scaling laws for super-and
subradiance are obtained and the limits of numerical studies are pointed out.
We also illustrate the cooperative nature of light scattering by considering an
incident laser field, where half of the beam has a phase shift. The
enhanced subradiance obtained under such condition provides an additional
signature of the role of coherence in the detected signal
The Occurence Rate, Polarization Character, and Intensity of Broadband Jovian Kilometric Radiation
The major observational features of one new component of Jupiter's radio emission spectrum, the broadband kilometer-wavelenth radiation or bKOM are described. The Voyager planetary radio astronomy experiments reveal that the overall occurrence morphology, total power, and polarization character of bKOM are strong functions of the latitude and/or local time geometry of the observations. The post-encounter data show a decline in the mean occurrence rates and power level of bKOM and, in particular, a depletion in the occurrence rate at those same longitudes where the detection rate is a maximum before encounter. Additionally, the polarization sense undergoes a permanent reversal in sign after encounter, whereas the time-averaged wave axial ratio and degrees of polarization remain relatively unchanged. No evidence of any control by Io is found. The strong dependence of the morphology on local time suggests a source whose beam is nearly fixed relative to the Jupiter-sun line
Evidence for an Io plasma torus influence on high-latitude Jovian radio emission
We report the discovery with the Ulysses unified radio and plasma wave (URAP) instrument of features in the Jovian hectometer (HOM) wavelength radio emission spectrum which recur with a period about 2–4% longer than the Jovian System III rotation period. We conclude that the auroral HOM emissions are periodically blocked from “view” by regions in the torus of higher than average density and that these regions rotate more slowly than System III and persist for considerable intervals of time. We have reexamined the Voyager planetary radio astronomy (PRA) data taken during the flybys in 1979 and have found similar features in the HOM spectrum. Contemporaneous observations by Brown (1994) show an [SII] emission line enhancement in the Io plasma torus that rotates more slowly than System III by the same amount as the HOM feature
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Security Clearance Process: Answers to Frequently Asked Questions
[Excerpt] The security clearance process is designed to determine the trustworthiness of an individual prior to granting him or her access to classified national security information. The process has evolved since the early 1950s, with antecedents dating to World War II. This report highlights some of the fundamental aspects of the process by providing answers to frequently asked questions
Saturnian kilometric radiation: Source locations
The surce locations of both polariation components of the saturn kilometer wavelength radiation were deduced using Voyager 1 and Voyager 2 planetary radio astronomy data and assumptions about radiation beam geometry. Radio source footprints were compared with the surface locations of saturns ultraviolet aurorae, its polar cap boundary, and its polar cusp
A radiometric Bode's Law: Predictions for Uranus
The magnetospheres of three planets, Earth, Jupiter, and Saturn, are known to be sources of intense, nonthermal radio bursts. The emissions from these sources undergo pronounced long term intensity fluctuations that are caused by the solar wind interaction with the magnetosphere of each planet. Determinations by spacecraft of the low frequency radio spectra and radiation beam geometry now permit a reliable assessment of the overall efficiency of the solar wind in stimulating these emissions. Earlier estimates of how magnetospheric radio output scales with the solar wind energy input must be revised greatly, with the result that, while the efficiency is much lower than previously thought, it is remarkably uniform from planet to planet. The formulation of a radiometric Bode's Law from which a planet's magnetic moment is estimated from its radio emission output is presented. Applying the radiometric scaling law to Uranus, the low-frequency radio power is likely to be measured by the Voyager 2 spacecraft as it approaches this planet
Ion-retarding lens improves the abundance sensitivity of tandem mass spectrometers
Ion-retarding lens which increases the abundance sensitivity of tandem magnetic-analyzer mass spectrometers measures isotopes of low abundance in mass positions adjacent to isotopes of high abundance. The lens increases the abundance sensitivity for isotopes lying farther from high abundance isotopes than the energy cutoff of the lens
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