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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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Thomson theory of arbitrarily intense elliptically polarized plane electromagnetic wave scattering by free electrons, solving electron equations of motion
Electron interaction with matter and differential cross section measurements for bremsstrahlung produced in coincidence with inelastically scattered electrons
Equipment and capabilities developed in investigation of K and L shell ionization cross sections, X ray intensity ratios, bremsstrahlung spectrum, coincidence, and inelastic electron scattering
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Solutions of the time dependent Fokker-Planck equation was found for accelerated electrons undergoing Coulomb collisions in a magnetized, fully ionized plasma. An exact solution was found for arbitrary pitch angle and energy distribution in a uniform background plasma. Then, for an inhomogeneous plasma, a solution was found for particles with small pitch angles. These solutions were used to calculate the temporal evolution of bremsstrahlung X-rays from short bursts of nonthermal electron beams, and these spectra were compared with observed high time resolution spectra of short timescale solar hard X-ray bursts. It is shown that the observed softening in time of the spectra rules out a homogeneous background and therefore the possibility of electrons being confined to the corona either because of converging magnetic field or high densities. The inhomogeneous solution was also applied to a model with constant coronal density and exponentially rising chromospheric density. The spectra are shown to be consistent with that produced by a collimated beam of electrons accelerated in the corona with certain given conditions. These conditions could be violated if large pitch angle electrons are present.
The propagation and absorption of the maser radiation during solar flares are examined through linear theory and electromagnetic particle simulations. It is shown using linear theory that strong absorption of the radiation should occur as it propagates toward the second harmonic layer, where the magnetic field is half as strong as in the emission region. Only radiation propagating nearly parallel to the magnetic field in a low-temperature plasma may be able to escape under certain limited conditions. Finite temperature effects can cause radiation propagating nearly perpendicular to the magnetic field to refract, causing enhanced absorption. Particle simulations are then used to evaluate the nonlinear response of the plasma as the maser radiation propagates through the absorption layer. It is shown that some of the maser radiation is able to escape through a process of absorption below the second harmonic of the local gyrofrequency and re-emission above it. The fraction able to escape is much higher than that predicted by linear theory, although the amount of escaping energy is only a small fraction of the incident energy.
This is an update to the ongoing series of presentations tracking the state of domestic proton facility access for the purpose of single event effects (SEE) testing of microelectronics devices and systems. This includes proton research facilities and oncology therapy centers.
This guideline is written to help facilitate adoption of COTS components by space flight projects by elucidating the radiation effects that various types of components are susceptible to, by describing potential mitigations, and by recommending component selection strategies that minimize radiation risks.
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Space Electronics needs Radiation Tolerance or hardness to withstand the harsh space environment: high-energy particles can change the state of the electronics or puncture transistors making them disfunctional. This viewgraph document reviews the use of CMOS Ultra Low Power Radiation Tolerant circuits for NASA's electronic requirements.
Rocketborne radiation detector observations of 10 cps periodicity in auroral electron precipitation
Energetic electron intensities radial flow diffusion in outer radiation belt near geomagnetic equator
The removal of radiation belt electrons through pitch-angle scattering by the observed obliquely propagating plasmaspheric whistler wave band is investigated. Electron lifetimes are calculated as a function of L and energy. The effects of high latitude interactions and of oblique wave propagation with the resulting diffusion at all cyclotron harmonics are quantitatively incorporated into the calculations. The inclusion of these effects appears to extend the role of whistler-driven electron pitch-angle diffusion to provide an explanation of the positioning of the quiet time radiation belt electron slot and the electron losses within the slot region.