Ion and electron angular distributions in the Io torus region of the Jovian magnetosphere

Angular distributions are presented of ion (∼0.5–2 MeV) and electron (>10 Mev) fluxes measured during the Voyager 1 spacecraft passage through the inner regions of the Jovian magnetosphere (radial distances from the planet ≲10 R J ). In the regions of peak flux intensities, just outside the orbit of Io, the ion angular distributions are most sharply peaked at 90° local pitch angle, a configuration consistent with diffusion of the particles inward from larger radial distances. Inside the orbit of Io the lower‐energy ions exhibit angular distributions depleted at 90° local pitch angles, suggesting the possibility of charge‐exchange scattering loss of these particles. In the vicinity of the Io flux tube, no significant effect is observed in the flux or pitch angle distributions of the ions. The relativistic electrons are depleted in the flux tube region and exhibit an asymmetrical pitch angle distribution, with more electrons appearing to arrive from the equatorial region (the direction of Io) than from the low‐altitude mirror point.