Evidence of Alfvenic Interactions in the Jovian Magnetosphere from the Juno Spacecraft

Abstract:

New insights provided by Juno energetic particle detector measurements indicate signatures of Alfvénic acceleration are more common than previously anticipated. Studies at Earth show that Alfvén waves can substantially accelerate plasma within the magnetosphere. At Jupiter, it is now predicted that Alfvénic acceleration is the dominant mechanism for generating the planet's powerful aurora. This acceleration occurs when the plasma thermal velocity is approximately equal to the Alfvén velocity, which at Jupiter occurs around the plasma sheet boundary. Using Juno JADE and MAG data, we investigate the regions surrounding the plasma sheet boundary layer in order to identify signatures of Alfvénic activity. Our study finds correlations between inertial scale magnetic field perturbations and variations in the local plasma population. We suggest that these signatures may be linked to turbulence in the plasma disk, which could be a source of heating for magnetospheric plasma observed in other studies.