The absolute cross sections of the reactions (1) N 18 (A«)C 12 , (2) W 5 (p,ay)C 12 , and (3) N 15 (^,T)0 16 have been measured from 0.2 to 1.6 Mev. The thick target yield of reaction (1) was also measured at 0.100 Mev. Resonances were found at 0.338, 1.05, and 1.210 Mev for reaction (1); at 0.429, 0.898, 1.210, and possibly 1.05 Mev for reaction (2); and at 1.05 Mev for reaction (3). Most of the resonances follow closely the shape of the single level dispersion formula. The 1.05-Mev resonance is asymmetric and cannot be explained as easily. The cross section of reaction (1) has been extrapolated to stellar energies and is given by

A detailed account is given of the energetic electron and proton populations as observed with Voyager 1 and 2 during their passes through the dawn magnetotail of Jupiter. In general, the results of the Pioneer 10 pass at 90° to the Jupiter‐sun line have been confirmed and extended. The region between 20 and 150 RJ is dominated by a thin plasma sheet, and open field lines were observed at 42 RJ at a magnetic latitude of only 15°. Trapped energetic electron and proton fluxes reach their maximum in the plasma sheet and decrease rapidly even a few degrees away from it. The spectra of trapped protons can be represented by an exponential in rigidity and have a characteristic energy of ∼50 keV. Proton anisotropies in the plasma sheet were consistent with corotation even at 100 RJ, but the preliminary analysis is not yet conclusive. A major proton acceleration event and several cases of field‐aligned proton streaming were observed. Comparable proton fluxes were observed in the plasma sheet by Voyager 1 and 2. The flux of >0.4‐MeV protons decreases by 3 orders of magnitude between 20 and 90 RJ and then remains relatively constant from there to the boundary layer near the magnetopause. Between 20 and 30 RJ in the antisolar direction, the trapping region has a latitudinal extent which is comparable to that observed during the inbound pass at −30° solar aspect. The plasma sheet positions in the magnetotail can be represented by a distorted disk which rotates about the Jovian spin axis. Fine structure in the data indicates longitudinal asymmetries with respect to the dipole orientation. Electron spectra in the outer magnetosphere, the magnetosheath, and interplanetary space are modulated by the Jovian longitude relative to the subsolar point; this confirms the Pioneer 10 and 11 results.

The observations of the cosmic-ray subsystem have added significantly to our knowledge of Jupiter's magnetosphere. The most surprising result is the existence of energetic sulfur, sodium, and oxygen nuclei with energies above 7 megaelectron volts per nucleon which were found inside of Io's orbit. Also, significant fluxes of similarly energetic ions reflecting solar cosmic-ray composition were observed throughout the magnetosphere beyond 11 times the radius of Jupiter. It was also found that energetic protons are enhanced by 30 to 70 percent in the active hemisphere. Finally, the first observations were made of the magnetospheric tail in the dawn direction out to 160 Jupiter radii.

Results from the cosmic-ray system on Voyager 2 in Saturn's magnetosphere are presented. During the inbound pass through the outer magnetosphere, the >/= 0.43-million-electron-volt proton flux was more intense, and both the proton and electron fluxes were more variable, than previously observed. These changes are attributed to the influence on the magnetosphere of variations in the solar wind conditions. Outbound, beyond 18 Saturn radii, impulsive bursts of 0.14- to > 1.0- million-electron-volt electrons were observed. In the inner magnetosphere, the charged particle absorption signatures of Mimas, Enceladus, and Tethys are used to constrain the possible tilt and offset of Saturn's internal magnetic dipole. At approximately 3 Saturn radii, a transient decrease was observed in the electron flux which was not due to Mimas. Characteristics of this decrease suggest the existence of additional material, perhaps another satellite, in the orbit of Mimas.

The passage of Pioneer 11 by Saturn provided a detailed view of a planetary magnetosphere that is intermediate between those of Jupiter and Earth in both scale and the complexity of its dynamic processes. It appears to have at least three distinct regions: (i) an outer magnetosphere, extending from 17 to 7.5 Saturn radii, that resembles that of Earth in many important aspects; (ii) a slot region, between 7.5 and 4 Saturn radii, where a marked decrease in all protons and low-energy electrons is observed; and (iii) an inner region, extending from 4 Saturn radii to the ring edge, that features a sharp increase in the proton flux extending to energies greater than 20 million electron volts. A cutoff of both proton and electron fluxes occurred just beyond the nominal edge of the A ring.