IRFP: Jupiter's Magnetosphere-Ionosphere System

Ray Licia C, Boulder CO

Investigators

Abstract

The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will support a twenty-four month research fellowship by Dr. Licia C. Ray to work with Dr. Nicholas Achilleos at University College London in London, United Kingdom. Magnetic braking, the process by which a star sheds angular momentum to its surrounding plasma and spins down, is an important process in solar system formation. Jupiter's interaction with its surrounding plasma disc is a local analog for this interaction. Thus far, magnetosphere-ionosphere (M-I) coupling models of angular momentum transport have not been able to reconcile in situ measurements of Jupiter's magnetospheric plasma (radial mass transport rates and angular velocity profiles) with observations of Jupiter's auroral emission - a bright signature of this coupling. However, previous models simplified the treatment of either the ionosphere or the magnetosphere, inadequately coupling the thermospheric and magnetospheric flows by neglecting the differential rotation allowed by field-aligned potentials. This research merges the University of Colorado magnetospheric model of angular momentum transfer with the University College London Jovian Ionosphere Model, building the first comprehensive system model of Jupiter's M-I coupling which treats the atmosphere and magnetosphere with equal sophistication and investigates how field-aligned potentials affect the atmospheric properties of the parent bodies and thus the net transport of angular momentum. By varying the planetary mass, magnetic field strength, and rotation rate this research will also quantify magnetic braking for early stars with applications to extra-solar system formation. This work will develop new international collaborations between the PI and the research group at University College London. It will contribute to the understanding of the coupled magnetosphere-ionosphere-thermosphere system of Jupiter and of early stars, which has inter-disciplinary applications to the fields of aeronomy, magnetospheric physics, and solar system formation.