Interplanetary solar-wind measurements by Mariner II.
Mariner II solar wind measurements including data on Venus electromagnetic radiation, space magnetic fields and charged particles, energy spectra, solar plasma, etc
INTERPLANETARY GAS↗
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Results for “ELECTROMAGNETIC RADIATION”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Dynamic stability of a gravity gradient stabilized satellite having long flexible antennas.
Radio astronomy satellite with extendible antennas achieves gravity gradient stabilization while receiving electromagnetic radiation, analyzing dynamic behavior and effect of passive damper
ANTENNA FIELD↗
Electromagnetic pulse from supernovae
Upper and lower limits to the radiated electromagnetic pulse from a supernova are calculated assuming that the mass fraction of the matter expanding inside the dipole magnetic field shares energy and maintains the pressure balance in the process. A supernova model is described in which the explosion occurs in old low-mass stars containing less than 10% hydrogen in their ejecta and a remnant neutron star is produced. The analysis indicates that although the surface layer of a star of 1 g/cu thickness may be shock-accelerated to an energy factor of about 100 and may expand into the vacuum with an energy factor approaching 10,000, the equatorial magnetic field will retard this expansion so that the inner, more massive ejecta layers will effectively accelerate the presumed canonical dipole magnetic field to greater velocities than would the surface layer alone. A pulse of 10 to the 46th power ergs in a width of about 150 cm will result which will not be affected by circumstellar matter or electron self-radiation effects. It is shown that interstellar matter will attenuate the pulse, but that charge separation may reduce the attenuation and allow a larger pulse to escape.
Colgate, S. A.↗
Inverse atmospheric radiative transfer problems - A nonlinear minimization search method of solution
The paper studies the inversion of the radiative transfer equation describing the interaction of electromagnetic radiation with atmospheric aerosols. The interaction can be considered as the propagation in the aerosol medium of two light beams: the direct beam in the line-of-sight attenuated by absorption and scattering, and the diffuse beam arising from scattering into the viewing direction, which propagates more or less in random fashion. The latter beam has single scattering and multiple scattering contributions. In the former case and for single scattering, the problem is reducible to first-kind Fredholm equations, while for multiple scattering it is necessary to invert partial integrodifferential equations. A nonlinear minimization search method, applicable to the solution of both types of problems has been developed, and is applied here to the problem of monitoring aerosol pollution, namely the complex refractive index and size distribution of aerosol particles.
Fymat, A. L.↗
Electron plasma waves in the solar wind - AMPTE/IRM and UKS observations
Selected events of plasma wave and electromagnetic emissions in the earth's electron fore-shock region have been studied. Strong emissions are observed in the plasma-wave band when the site of the satellite is magnetically connected to the bow shock. These emissions are generally highly fluctuating. Under certain conditions one observes electromagnetic radiation at the second harmonic produced locally. Electromagnetic emission generated at a position far away from the site of the spacecraft is occasionally detected giving rise to remote sensing of the bow shock. These emissions are related to energetic electron fluxes.
Treumann, R. A.↗
Technique for Radiometer and Antenna Array Calibration - TRAAC
Highly sensitive receivers are used to detect minute amounts of emitted electromagnetic energy. Calibration of these receivers is vital to the accuracy of the measurements. Traditional calibration techniques depend on calibration reference internal to the receivers as reference for the calibration of the observed electromagnetic energy. Such methods can only calibrate errors in measurement introduced by the receiver only. The disadvantage of these existing methods is that they cannot account for errors introduced by devices, such as antennas, used for capturing electromagnetic radiation. This severely limits the types of antennas that can be used to make measurements with a high degree of accuracy. Complex antenna systems, such as electronically steerable antennas (also known as phased arrays), while offering potentially significant advantages, suffer from a lack of a reliable and accurate calibration technique. The proximity of antenna elements in an array results in interaction between the electromagnetic fields radiated (or received) by the individual elements. This phenomenon is called mutual coupling. The new calibration method uses a known noise source as a calibration load to determine the instantaneous characteristics of the antenna. The noise source is emitted from one element of the antenna array and received by all the other elements due to mutual coupling. This received noise is used as a calibration standard to monitor the stability of the antenna electronics.
Meyer, Paul↗
A novel means to generate high pressure
Diamond anvil cells are the most popular means of generating pressures above 2 GPa. However, in many experiments, such as nuclear magnetic resonance and x-ray absorption, the metallic pressurizing gasket (which confines much of the sample) represents an occluding barrier that requires a low Z gasket material (e.g., Be), a split gasket, or other means to enable better coupling of the sample to electromagnetic radiation. In this paper, we demonstrate a novel method for generating high pressures that confines the sample just above the plane of the gasket by using a diamond with a laser hole drilled into the center of the tip. The sample is then confined by the hole, which is sealed by a flat gasket that fits over the hole. When load is applied to the diamonds, metal flows from the deformed gasket into the hole thereby pressurizing the sample similarly to how a piston pressurizes gas inside a cylinder. The pressurized sample is above the metallic gasket plane just inside the tip of the diamond, and thus easily accessible via x rays or visible light that skims just above the plane of the gasket providing an enhanced aperture of radiation collection. Furthermore, we have demonstrated the utility of this method by obtaining Raman spectra of SnC 2 O 4 and x-ray diffraction spectra of seleno-DL-cystine, all at high pressures.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Radiation Effects Design Handbook. Section 4 - Transistors
Neutron, electron, proton, and electromagnetic radiation effects on transistors - handbook
Drennan, J. E.↗
Radiation Pressure Measurements on Micron Size Individual Dust Grains
Measurements of electromagnetic radiation pressure have been made on individual silica (SiO2) particles levitated in an electrodynamic balance. These measurements were made by inserting single charged particles of known diameter in the 0.2 micron to 6.82 micron range and irradiating them from above with laser radiation focused to beam-widths of approx. 175-400 micron, at ambient pressures approx. 10(exp -3) to 10(exp -4) torr. The downward displacement of the particle due to the radiation force is balanced by the electrostatic force indicated by the compensating dc potential applied to the balance electrodes, providing a direct measure of the radiation force on the levitated particle. Theoretical calculations of the radiation pressure with a least-squares fit to the measured data yield the radiation pressure efficiencies of the particles, and comparisons with Mie scattering theory calculations provide the imaginary part of the refractive index of silica and the corresponding extinction and scattering efficiencies.
Abbas, M. M.↗
IPRT Polarized Radiative Transfer Model Intercomparison Project-Phase A
The polarization state of electromagnetic radiation scattered by atmospheric particles such as aerosols, cloud droplets, or ice crystals contains much more information about the optical and microphysical properties than the total intensity alone. For this reason an increasing number of polarimetric observations are performed from space, from the ground and from aircraft. Polarized radiative transfer models are required to interpret and analyse these measurements and to develop retrieval algorithms exploiting polarimetric observations. In the last years a large number of new codes have been developed, mostly for specific applications. Benchmark results are available for specific cases, but not for more sophisticated scenarios including polarized surface reflection and multi-layer atmospheres. The International Polarized Radiative Transfer (IPRT) working group of the International Radiation Commission (IRC) has initiated a model intercomparison project in order to fill this gap. This paper presents the results of the first phase A of the IPRT project which includes ten test cases, from simple setups with only one layer and Rayleigh scattering to rather sophisticated setups with a cloud embedded in a standard atmosphere above an ocean surface. All scenarios in the first phase A of the intercomparison project are for a one-dimensional plane-parallel model geometry. The commonly established benchmark results are available at the IPRT website
radiative transfer↗
The Software Element of the NASA Portable Electronic Device Radiated Emissions Investigation
NASA Langley Research Center's (LaRC) High Intensity Radiated Fields Laboratory (HIRF Lab) recently conducted a series of electromagnetic radiated emissions tests under a cooperative agreement with Delta Airlines and an interagency agreement with the FAA. The frequency spectrum environment at a commercial airport was measured on location. The environment survey provides a comprehensive picture of the complex nature of the electromagnetic environment present in those areas outside the aircraft. In addition, radiated emissions tests were conducted on portable electronic devices (PEDs) that may be brought onboard aircraft. These tests were performed in both semi-anechoic and reverberation chambers located in the HIRF Lab. The PEDs included cell phones, laptop computers, electronic toys, and family radio systems. The data generated during the tests are intended to support the research on the effect of radiated emissions from wireless devices on aircraft systems. Both tests systems relied on customized control and data reduction software to provide test and instrument control, data acquisition, a user interface, real time data reduction, and data analysis. The software executed on PC's running MS Windows 98 and 2000, and used Agilent Pro Visual Engineering Environment (VEE) development software, Common Object Model (COM) technology, and MS Excel.
Koppen, Sandra V.↗
Substrate Channeling in Compartmentalized Nanoreactors
Not Available
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Theoretical studies on rapid fluctuations in solar flares
Rapid fluctuations in the emission of solar bursts may have many different origins e.g., the acceleration process can have a pulsating structure, the propagation of energetic electrons and ions can be interrupted from plasma instabilities and finally the electromagnetic radiation produced by the interaction of electrostatic and electromagnetic waves may have a pulsating behavior in time. In two separate studies the conditions for rapid fluctuations in solar flare driven emission were analyzed.
Vlahos, Loukas↗
Chapter 11 - Aerosol–Radiation Interactions
This chapter describes the aerosol–radiation interactions of absorption, scattering, and emission of electromagnetic radiation by atmospheric aerosol particles, which alter the fluxes of radiative energy in the atmosphere. The chapter begins by defining some fundamental processes, including the particle physical and optical properties that determine the amount of light scattered and absorbed. It then outlines the factors that determine the radiative effect of aerosol–radiation interactions in the atmosphere, including the solar zenith angle, the properties of underlying surfaces, the influence of clouds, and atmospheric temperature, and humidity profiles. It defines the magnitude of the aerosol radiative effect on the climate system as well as the radiative forcing over the industrial period determined from satellite measurements and models for clear-sky and all-sky conditions.
scattering absorption↗
Effects of the atmosphere on remote sensing
The interaction between electromagnetic radiation and the earth's atmosphere is considered, taking into account windows in the electromagnetic spectrum, solar and terrestrial radiation, physical properties of the atmosphere, and clouds. The characteristics of upwelling radiation in the visible wavelengths are discussed along with infrared radiation and microwaves. Attention is given to radiant emittance, radiance, contrast, effects of atmospheric turbulence, ocean color, and questions concerning the classification of surface features with the aid of computers.
Fraser, R. S.↗
Radiation from a localized Langmuir oscillation in a uniformly magnetized plasma
The electromagnetic radiation at the first and second harmonics of the electron plasma frequency from a localized Langmuir perturbation is computed for the case of a uniformly magnetized plasma. It is assumed that the localized perturbations in both the electrostatic field and plasma density have cylindrical symmetry about the direction of the ambient magnetic field. The analysis is initially performed for such an arbitrary localized perturbation, and then applied to treat the case of a quasi-planar Langmuir soliton propagating in the direction of the magnetic field. An extensive numerical study of the angular dependence of the radiation spectrum as a function of the ratio of the electron plasma and cyclotron frequencies is described.
Freund, H. P.↗
Radiation Pressure Measurements on Micron-Size Individual Dust Grains
Measurements of electromagnetic radiation pressure have been made on individual silica (SiO2) particles levitated in an electrodynamic balance. These measurements were made by inserting single charged particles of known diameter in the 0.2- to 6.82-micron range and irradiating them from above with laser radiation focused to beam widths of approximately 175- 400 microns at ambient pressures particle due to the radiation force is balanced by the electrostatic force indicated by the compensating dc potential applied to the balance electrodes, providing a direct measure of the radiation force on the levitated particle. Theoretical calculations of the radiation pressure with a least-squares fit to the measured data yield the radiation pressure efficiencies of the particles, and comparisons with Mie scattering theory calculations provide the imaginary part of the refractive index of SiO2 and the corresponding extinction and scattering efficiencies.
Abbas, M. M.↗
Electromagnetic processes in the atmosphere of pulsars
The work consists of two parts. The first deals with the fine structure of radio pulses. Based on kinetic theory, processes occurring in the plasma shell of a pulsar when external electromagnetic radiation is present are investigated. It is shown that electromagnetic waves cause electrons to drift relative to ions, and initiate longitudinal oscillations. A dispersion equation describing the longitudinal oscillations in magnetized plasma is derived. Conditions for excitation of oscillations are found. Correlation functions of electron density are calculated, along with the coefficients of electromagnetic wave scattering. It is shown that variations in the amplitude of pulsar pulses are associated with scintillations caused by fluctuations in the plasma electron density. The second part of the study presents a mechanism for the radio emission of pulsars. The model of a rotating and a pulsating star, a neutron star with dipolar or more complex magnetic field, is examined.
Yukhimuk, A. K.↗