Abstract
AbstractWe present Jovian auroral observations from the 2014 January Hubble Space Telescope (HST) campaign and investigate the auroral signatures of radial transport in the magnetosphere alongside contemporaneous radio and Hisaki EUV data. HST FUV auroral observations on day 11 show, for the first time, a significantly superrotating polar spot poleward of the main emission on the dawnside. The spot transitions from the polar to main emission region in the presence of a locally broad, bright dawnside main emission feature and two large equatorward emission features. Such a configuration of the main emission region is also unreported to date. We interpret the signatures as part of a sequence of inward radial transport processes. Hot plasma inflows from tail reconnection are thought to flow planetward and could generate the superrotating spot. The main emission feature could be the result of flow shears from prior hot inflows. Equatorward emissions are observed. These are evidence of hot plasma injections in the inner magnetosphere. The images are thought to be part of a prolonged period of reconnection. Radio emissions measured by Wind suggest that hectometric (HOM) and non‐Io decametric (DAM) signatures are associated with the sequence of auroral signatures, which implies a global magnetospheric disturbance. The reconnection and injection interval can continue for several hours.
Highlights
Iogenic plasma generated in the inner magnetosphere is transported radially outward through a quasi steady state process to the outer magnetosphere where it is lost down the magnetotail
We present Jovian auroral observations from the 2014 January Hubble Space Telescope (HST) campaign and investigate the auroral signatures of radial transport in the magnetosphere alongside contemporaneous radio and Hisaki extreme ultraviolet (EUV) data
Radio emissions measured by Wind suggest that hectometric (HOM) and non-Io decametric (DAM) signatures are associated with the sequence of auroral signatures, which implies a global magnetospheric disturbance
Summary
Iogenic plasma generated in the inner magnetosphere is transported radially outward through a quasi steady state process to the outer magnetosphere where it is lost down the magnetotail. At Earth, auroral features have been shown to be a manifestation of magnetospheric transport processes. Auroral features are measured in system III (λIII), a jovicentric longitude-latitude grid which corotates with the planet with a period of 9.925 h, as defined in Dessler [1983]. In the middle magnetosphere (15–40 RJ), the angular speed of Iogenic plasma falls as it is centrifugally driven outward. A field-aligned current system that closes through radial currents in the equator is responsible for transferring angular momentum in order to maintain partial corotation. The upward current produces Jupiter’s auroral main emission [Hill, 2001; Cowley and Bunce, 2001]. Its primary variability corresponds to changes in mass loading and mass outflow rate in the middle magnetospheric “corotation breakdown region” [Nichols, 2011; Ray et al, 2012]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
