Variability of Jupiter’s Main Auroral Emission in Response to Magnetospheric Hot Plasma Injections

Sarah Victoria Badman1, Bertrand Bonfond2, Masaki Fujimoto3, Masato Kagitani4, Yasumasa Kasaba5, Satoshi Kasahara6, Tomoki Kimura7, Henrik Melin8, Go Murakami9, Jonathan D Nichols10, Takeshi Sakanoi11, Andrew Steffl12, Chihiro Tao13, Fuminori Tsuchiya4, Takeru Uno4, Atsushi Yamazaki9, Mizuki Yoneda4, Ichiro Yoshikawa14 and Kazuo Yoshioka3, (1)University of Lancaster, Lancaster, United Kingdom, (2)Université de Liège, LPAP - STAR Institute, Liege, Belgium, (3)JAXA Japan Aerospace Exploration Agency, Sagamihara, Japan, (4)Tohoku University, Sendai, Japan, (5)Tohoku University, Department of Geophysics, Graduate School of Science, Sendai, Japan, (6)ISAS Institute of Space and Astronautical Science, Kanagawa, Japan, (7)Japan Aerospace Exploration Agency, Kanagawa, Japan, (8)University of Leicester, School of Physics and Astronomy, Leicester, United Kingdom, (9)ISAS/JAXA, Sagamihara, Kanagawa, Japan, (10)University of Leicester, School of Physics and Astronomy, Leicester, LE1, United Kingdom, (11)PPARC, Tohoku University, Sendai, Japan, (12)Southwest Research Institute, Boulder, CO, United States, (13)IRAP, Toulouse, France, (14)University of Tokyo, Bunkyo-ku, Japan
Abstract:
We present observations of Jupiter’s FUV aurora acquired by the Hubble Space Telescope during a two-week interval in January 2014. The variability of the main auroral emission was studied using latitudinal profiles of intensity. The main oval intensity was found to be reduced when bright patches of diffuse emission were present at lower latitudes. These low latitude emissions are interpreted as the signatures of hot plasma injections from the outer magnetosphere, a process which has previously been related to interchange between the flux tubes from the outer magnetosphere and outward-moving flux tubes loaded with iogenic plasma. The main emission was also observed to broaden and shift in latitude, and occasionally display a double peak structure. These observations are interpreted with reference to the expected changes in auroral field-aligned currents associated with the replacement of the radially-stretched, mass-loaded flux tubes in the middle magnetosphere by more dipolar flux tubes containing rarefied hot plasma. 
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