GEOMAGNETICALLY TRAPPED RADIATION FROM FAST COSMIC-RAY ALBEDO NEUTRONS. Thesis

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1963

OSTI ID:4132335

Lenchek, A M

The intensity, energy spectrum, and angular distribution of fast albedo neutrons generated by the galactic cosmic radiation were calculated. The angular distribution is peaked in the horizontal direction with an angular width that is inversely proportional to the neutron momentum. The source function of the global component, which results from the albedo distribution, was calculated. It is quite uniform with respect to altitude and pitch angle over the inner belt, varying only very slowly as compared to the variation of loss rates or lifetimes. The latter were studied for the relevant collision processes. For fast protons the only important processes are ionization loss in Coulomb collisions and (at very high energy) absorption in nonelastic nuclear collisions. The lifetimes are therefore governed by the air density integrated over the path of the particle. In order to calculate the integrated air density it is sufficient that the altitude of the mirror traces be determined vs longitude, however these must be mapped in the true (distorted) magnetic field rather than in any dipole representation. This was carried out, yielding angular (spatial) distributions. The fact that the angular distribution of the albedo is energy dependent is shown to affect the energy spectrum of the source function, steepening it significantly. The equilibrium energy spectrum that is then calculated is in good agreement with measured spectra. The dependence upon pitch angle of the equilibrium energy spectrum was investigated. The distribution of trapped protons that result from the impact of solar cosmic rays has also been computed, with results that agree with experiment. We concluded that the fast neutron albedo quantitatively accounts for the trapped protons. High energy albedo neutrons also inject relativistic electrons. The energy spectrum of such electrons is similar to the spectrum measured above 1 Mev in the outer belt. However the predicted intensity is much smaller than that observed. (TCO)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-18-004422
• OSTI ID: 4132335
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ABSORPTION
ALBEDO
ANGULAR DISTRIBUTION
ATMOSPHERE
BETA DECAY
COSMIC RADIATION
DENSITY
DISTRIBUTION
EARTH
ELECTRIC POTENTIAL
ELECTRONS
EMISSION
ENERGY
FAST NEUTRONS
INJECTION
INTERACTIONS
IONIZATION
LEVELS
LIFETIME
LOSSES
MAGNETIC FIELDS
MOMENTUM
NEUTRONS
NUMERICALS
PHYSICS
PROTONS
RADIATION BELTS
REFLECTION
SUN
TRAJECTORIES