AGS-PRF: To what Extent are Jupiter's Magnetosphere and Aurora Influenced by the Solar Wind?

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The solar wind of charged particles and magnetic fields blowing outward from the Sun interacts with Jupiter's magnetosphere, the region of space controlled by its magnetic field. But does this interaction make a significant difference to the Jovian magnetospheric dynamics as it does at Earth? Most believe that the effects of any interaction with the solar wind are completely overwhelmed by the effects of the rapid rotation of Jupiter's strong magnetic field and the extended torus of heavy ions created by Io's volcanoes. This question continues to be an area of active research and debate due in part to the lack of available solar wind measurements near Jupiter's orbit. The study will use a model that propagates solar wind conditions measured near Earth out to Jupiter in order to estimate solar wind conditions there. The work will examine observations of magnetic fields and particles within Jupiter's magnetosphere by the Galileo spacecraft, and images of Jupiter's aurora taken by the Hubble Space Telescope, to determine whether changes in these data may be statistically associated with changes in the modeled solar wind conditions. The results of this work will add to our knowledge of how planetary magnetospheres work, putting our understanding of the Earth's magnetosphere into a broader context, and informing the study of star-exoplanet interactions. This grant supports the training of a female postdoctoral student. Results from the research and other recent advances in space plasma physics will be presented to the public during the Boston University Astronomy Department's weekly public open night at the campus observatory while groups are waiting to use the telescopes. Additionally, the proposer will mentor graduate students at Boston University through the Graduate Women in Science and Engineering program. Previous attempts have been made to model solar wind conditions at Jupiter based on solar wind conditions near Earth but the success of this technique has so far been limited by the large uncertainties in the arrival times of solar wind disturbances. These uncertainties in turn make linking dynamical responses of Jupiter's magnetosphere to particular solar wind disturbances problematic. The innovation in this proposal is to use the observed compression of Jupiter's magnetic field in response to the dynamic pressure changes in the solar wind to refine the arrival time of disturbances in the solar wind and minimize uncertainties in timing. The statistical correlation (or lack thereof) between the arrival of solar wind disturbances and changes in Jupiter's magnetosphere and aurora will test the importance of solar wind interactions. Of particular importance, it will address whether quasi-periodic behavior observed in Jupiter's magnetosphere might be controlled by the solar wind. This study will also determine how Jupiter's main auroral emissions respond to changing solar wind conditions, and compare findings to theories and models.