Characterization of Jupiter's secondary auroral oval and its response to hot plasma injections. Issue 6 (28th June 2017)

• Record Type: Journal Article
• Authors: Gray, R. L.; Badman, S. V.; Woodfield, E. E.; Tao, C.
• Is Part Of: Journal of geophysical research. Volume 122:Issue 6(2017)
• Page Start: 6415
• Page End: 6429
• Publication Date: 2017-06-28
• Subjects: Jupiter -- aurora -- plasma injections -- HST -- wave‐particle interactions; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1002/2017JA024214
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: We present Jovian auroral observations from the 2014 January Hubble Space Telescope (HST) campaign and characterize the auroral second oval feature with particular attention to the response to hot plasma injections. The location of the second oval feature lies between the Ganymede and Europa moon footprint contours between 150 and 240° system III longitude, corresponding to a source in the inner magnetosphere between 9 and 13 R J . At the examined longitudes, this is in the same region of 11–16 R J known as the pitch angle distribution boundary, beyond which electrons are thought to be scattered into a field‐aligned configuration and cause auroral precipitation. The feature is enhanced in both brightness and longitudinal spread 1–3 days after large hot plasma injections. The precipitating electrons have a higher‐energy and lower flux than the electrons generating large injection signatures. We suggest that wave‐particle interactions are responsible for the scattering of electrons in this region. We also suggest that the plasma injections can act as a temperature anisotropy and particle source to enhance electron scattering into the aurora and the brightness of the second oval feature. Changes to the magnetic field topology around an injection may also generate shear Alfvén waves and therefore accelerate electrons parallel to the magnetic field resulting in precipitation. Key Points: During January 2014 Jupiter's UV aurora exhibits a lower latitude second oval feature The magnetospheric source region lies around 9–13 R J and close to hot plasma injections Wave‐particle interactions may enhance the oval brightness 1–3 days after the hot plasma injections