Simple analytic solutions appropriate for galactic cosmicray modulation.
Abstract
Exact analytic solutions, for the galactic cosmicray density, to the standard timeindependent spherically symmetric convectiondiffusionadiabatic deceleration equation governing the transport of cosmic rays in the interplanetary medium are presented. It is assumed that the solarwind speed is constant and that the spatial diffusion coefficient is given by a power law, independent of distance from the sun, in accordance with Pioneer 10 and 11 measurements and recent calculations. One solution depicts with decreasing distance from the sun the energy loss and intensity decrease of an interstellar spectrum which is peaked in momentum. From this solution others are constructed which (1) are extremely simple analytically; (2) are sufficiently general both to yield excellent agreement with observations near earth and to demonstrate quantitatively the sensitivity of derived interstellar spectra on the forms assumed in the inner solar system, particularly at low energies; and (3) promise to replace the standard convectiondiffusion solution often utilized in data analysis and modulation estimates, while providing a useful tool for future research involving cosmicray modulation.
 Publication:

The Astrophysical Journal
 Pub Date:
 September 1977
 DOI:
 10.1086/155503
 Bibcode:
 1977ApJ...216..635C
 Keywords:

 Cosmic Rays;
 Galactic Radiation;
 Interplanetary Medium;
 Particle Diffusion;
 PlasmaParticle Interactions;
 Solar Wind;
 Energy Dissipation;
 Energy Spectra;
 Modulation;
 Particle Flux Density;
 Pioneer Space Probes;
 Space Radiation