High-energy trapped radiation penetrating the rings of Saturn

Journal Article · Sat Nov 01 04:00:00 EST 1980 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA085iA11p05785· OSTI ID:6745922

Chenette, D L; Cooper, J F; Eraker, J H; Pyle, K R; Simpson, J A

Electrons and protons in the energy ranges 2--25 MeV and >67 MeV, respectively, have been discovered throughout the entire equatorial region inward from the outer edge of the A ring at L=2.3 to the periapsis of the Pioneer trajectory at Lapprox.1.3. The trapped radiation which populates Saturn's magnetosphere byond L=2.3 is totally absent in this region. The electron measurements include (1) a differential energy spectrum proportionalE/sup -0.6/, (2) an L dependence consistent with L/sup 2.8/, and (3) an intensity of approx.0.05 el/cm/sup 2/ s sr near L=2 for the energy range 7--17 MeV (a factor of 5 times the interplanetary quiettime flux in this energy range.) The proton measurements display an L dependence of L/sup 2/ with a flux level of approx.6 x 10/sup -2/ protons/cm/sup 2/ s sr above 67 MeV, just inside the edge of the A ring. The pitch angle distributions of both the electrons and protons are consistent with isotropy in the dipole magnetic field. It is argued from these results that the electrons and protons are trapped and thus penetrate the A-B-C rings. However, from the above experimental evidence it is concluded that this trapped radiation is not remnant radiation from the trapped radiation region beyond L=2.3. We find that these measurements are consistent with a model for spalsh albedo production of electrons and protons resulting from the bombardment of the atmosphere and/or rings of Saturn by cosmic ray protons with energies above the Stoermer cut-off at the magnetic latitudes of production. These secondary particles are then observed as trapped radiation propagating along the appropriate field lines crossing the ring plane. We also show that electron production may occur through ..pi../sup + -/..--> mu../sup + -/ ..-->..e/sup + -/ decay chain which yields an L dependence of L/sup 2.8/ for pions.

• Research Organization: Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637
• OSTI ID: 6745922
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 85:A11; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALBEDO
ATMOSPHERES
BARYONS
ELECTRONS
ELEMENTARY PARTICLES
ENERGY SPECTRA
FERMIONS
HADRONS
INCLINATION
LEPTONS
NUCLEONS
PIONEER SPACE PROBES
PLANETARY ATMOSPHERES
PLANETARY MAGNETOSPHERES
PLANETS
PROTONS
RADIATION BELTS
SATURN PLANET
SPACE VEHICLES
SPECTRA
TRAPPED ELECTRONS
TRAPPED PROTONS
VEHICLES