Pitch‐angle diffusion by whistler mode waves near the Io plasma torus

As Voyager 1 traversed the inner radiation belt of Jupiter, wave‐particle interactions involving energetic electrons and whistler mode turbulence were strongly affected by the presence of the Io plasma torus. Within the high density torus the resonant electron energy was low and the associated high index of refraction yielded high B‐to‐E ratios for the wave fields, leading to very strong pitch‐angle scattering. We show that significant spatial and temporal variations in plasma conditions produced large fluctuations in local scattering times, and we discuss the problems associated with the evaluation of precipitation lifetimes.