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. One possible such process is the convection of the magnetized ions to the reconnection site in the distant night magnetosphere where the ions are released 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 the field lines into the loss cone and then into the upper atmosphere. The magnetic field measurements on the Galileo spacecraft are used to determine the radial variation of wave power that could cause pitch angle scattering of these particles. We, conclude that, while this process does act, it is too weak to cause significant losses from the equatorial magnetosphere. (C) 2001 Elsevier Science Ltd. All rights reserved.