Ultra-low-frequency waves in the Jovian magnetosphere: causes and consequences

Mass loading of the Jovian magnetosphere at Io requires a process to remove those ions from the magnetic field in order to maintain a steady state. On e possible such process is the convection of the magnetized ions to the rec onnection site in the distant night magnetosphere where the ions are releas ed from the closed held lines and leave the Jovian system via the magnetic tail. A competing process is the pitch angle scattering of the ions from th e field lines into the loss cone and then into the upper atmosphere. The ma gnetic field measurements on the Galileo spacecraft are used to determine t he radial variation of wave power that could cause pitch angle scattering o f these particles. We, conclude that, while this process does act, it is to o weak to cause significant losses from the equatorial magnetosphere. (C) 2 001 Elsevier Science Ltd. All rights reserved.