Dynamics of the flares in the active polar region of Jupiter

Abstract

AbstractThe duskside of the polar region of Jupiter's UV aurorae, called the active region, sometimes exhibits quasiperiodic (QP) flares on timescales of 2–3 min. Based on Hubble Space Telescope Far‐UV time‐tag images, we show for the first time that the Northern Hemisphere also displays QP flares. The area covered by these flares can reach up to 2.4 × 108 km2 (i.e., the whole active region) but often only involves an area an order of magnitude smaller. Using a magnetic field mapping model, we deduced that these areas correspond to the dayside outer magnetosphere. In our data set, quasiperiodic features are only seen on half of the cases, and even on a given observation, a region can be quiet for one half and blinking on the other half. Consecutive observations in the two hemispheres show that the brightening can occur in phase. Combined with the size and location of the flares, this behavior suggests that the QP flares most likely take place on closed magnetic field lines.