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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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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1968

An improved model for cosmic-ray propagation.

Cosmic ray propagation Jokipii model modification, taking into account particle mirroring to determine diffusion coefficient by limited portion of field spectrum

Noerdlinger, P. D.↗
NASA NTRS1968

Cosmic-ray propagation.

Cosmic ray propagation, discussing interstellar matter effect on composition and diffusion effect necessary to study radiation models

Fichtel, C. E.↗
NASA NTRS1972

The physical theory of one dimensional galactic cosmic-ray propagation in the atmosphere

An analytical theory of atmospheric cosmic-ray propagation is developed based on a phenomenological model of hadron-nucleus collisions. This model correctly predicts the sea level cosmic-ray nucleon, pion and muon spectra, the cosmic-ray ionization profile in the atmosphere, and neutron flux and density profiles in the atmosphere. It is concluded that the large scale properties of atmospheric cosmic-rays can be accurately predicted on the basis of a nucleonic cascade with all secondaries mediated by pion production. Implications for energy independence of cross sections, the recent 70 GeV results from Serpukhov, and nucleonic relaxation rates in the atmosphere are discussed.

Obrien, K.↗
NASA NTRS1966

Cosmic-ray propagation. I.

Charged particle motion in random magnetic field, describing time evolution of particle distribution in pitch angle and position in terms of Fokker- Planck coefficients

INTERPLANETARY MAGNETIC FIELD↗
NASA NTRS1967

Cosmic-ray propagation processes. I.

Time dependency, anisotropy, propagation and spectral properties of cosmic radiation released by solar flares during sunspot activity

SUNSPOT CYCLE↗
DOE OSTI2025

A Unified Model of Cosmic-Ray Propagation and Radio Extreme Scattering Events from Intermittent Interstellar Structures

Intermittent magnetic structures are a plausible candidate for explaining cosmic-ray (CR) diffusion rates derived from observed CR energy spectra. Independently, studies of extreme scattering events (ESEs) of radio quasars and pulsar scintillation have hinted that very straight, large aspect ratio magnetic current sheets may be responsible for the localized large scattering of radio waves. The required shortest axis of the typical structures producing ESEs is of the same scale (∼au) as the gyroradii of ∼GeV CRs. In this Letter, we propose that the same magnetic/density sheets can produce large scattering of both CRs and radio waves. We demonstrate that the geometry and volume-filling factor of the sheets derived from quasar ESEs can explain the observed mean free path of GeV CRs without introducing free parameters. The model places constraints on the sheet geometry, such as straightness and large aspect ratio, and assumes that the statistics of the sheets are similar throughout the Galactic volume. We therefore discuss observational tests of the sheet model, which includes observations of echoes in pulsars and fast radio bursts, gravitationally lensed quasars, the distribution of ESE durations, and spatial correlations between ESE events and rotation measure fluctuations. Such tests will be enabled by upcoming wide-field radio instruments, including the Canadian Hydrogen Observatory and Radio-transient Detector and Deep Synoptic Array 2000 Antennas.

Kempski, Philipp [Princeton Univ., NJ (United Stat↗
NASA NTRS1973

Cosmic-ray propagation and modulation in the interplanetary medium

An attempt is made to show the present state of the observations and theories relevant to the modulation within the solar cavity of galactic cosmic rays with kinetic energies in the range 10 MeV to 10 GeV. In particular it is shown that the modulation of electrons, protons, and helium nuclei over the last half-solar-cycle can well be reproduced with current models, and the radial gradients and anisotropics associated with these models are shown. The origin within the energy spectrum of the low energy particles and their properties is discussed, as well as the verification of energy loss processes.

Gleeson, L. J.↗