A mosaic of Jupiter (304 deg; CML) at 3.4 microns wavelength obtained on 12 January 1992. A meridian plane projection of field lines originating beyond 30 R_j and at the orbital radial distance of Io (5.9 R_j) are superposed on the mosaic. The leftmost field line is traced from the instantaneous orbital position of Io at 79 deg Io phase. Most of the H₃+ emission originates from the auroral oval approximated by the footprint of the last closed field line. Two faint emission features due to the Io-Jupiter interaction can seen near the leftmost limb of the planet just equatorward of the aurora in both hemispheres. The featureless background emission distributed across the planetary disc is due to ionospheric H₃+ emission. (Figure from Connerney et al., "Images of H₃+ Emission at the Foot of the Io Flux Tube in Jupiter's Atmosphere",Science 262, 1035-1038, 1993)