SOLAR MODULATION OF GALACTIC COSMIC RAYS: TECHNIQUES & APPLICATIONS (SHOCK ACCELERATION, ANTIPROTONS)

<p>This thesis covers four topics in the theory of interplanetary cosmic-ray propagation:</p><p>The first part involves the time-dependent, spherically-symmetric, solar modulation of galactic cosmic rays. A numerical technique was introduced for the solution of this problem. A model for the solar-cycle variation in cosmic-ray intensity illustrated this method, using enhanced particle scattering regions. This model accounted for at least three key sets of observations: the cosmic-ray radial intensity gradients; the decrease in cosmic-ray intensity over the solar cycle; and the hysteresis between low and high-energy cosmic rays.</p><p>The second section contains an attempt to explain recent observations which show that cosmic-ray electrons are returning to higher intensities, characteristic of solar minimum, faster than cosmic-ray protons of about the same energy, the reverse of the previous eleven-year cycle. This section tests a suggested reason for the observations: velocity and rigidity differences between protons and electrons due to their different masses. The time-dependent, spherically-symmetric model of the first section generated the necessary lag in the relative recovery rates, but only as observed in the previous solar cycle.</p><p>The third section involves the solar modulation of galactic antiprotons. It appears that a recent low-energy measurement of these particles has given cosmic-ray theorists trouble devising an interstellar spectrum to fit the observations. Using a steady-state, spherically-symmetric, numerical modulation code, a solution that reasonably fits the observed 1980 galactic proton spectrum at 1 AU implied that the modulation used for the data interpretation has been significantly underestimated.</p><p>The final section contains a spherically-symmetric, steady-state calculation of the effects of a strong termination shock in the heliosphere. In the end, high-energy particles cooling down in the upstream solar wind overwhelmed any accelerated low-enegy particles, those which would be most affected by the shock. The overall effect of a shock on the near-Earth spectra seems negligible.</p>

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

Dissertation

Year

1984

Author dc:creator

• PERKO, JOHN STEVEN

• Physics
• Astronomy and Astrophysics

Repository record dc:identifier

https://scholars.unh.edu/dissertation/1442

OAI identifier oai:identifier

oai:scholars.unh.edu:dissertation-2441