When the Chandra X-Ray Space Telescope observed Jupiter for its entire 10-hour rotation, the northern auroral X-rays were discovered to be due to a single 'hot spot' that pulsates with a period of 45 minutes, similar to high-latitude radio pulsations previously detected by NASA's Galileo and Cassini spacecraft.
Chandra's ability to pinpoint the source of the X-rays has cast serious doubt on this model. Ions coming from near Io's orbit cannot reach the observed high latitudes. The energetic ions responsible for the X-rays must come from much further away than previously believed.
One possibility is that particles flowing out from the Sun are captured in the outer regions of Jupiter's magnetic field (image below), then accelerated and directed toward its magnetic pole. Once captured, the ions would bounce back and forth in the magnetic field, from Jupiter's north pole to south pole in an oscillating motion that could explain the pulsations.
The Daily Galaxy via Chandra Space Observatory
Image Credit: NASA/CXC/SWRI/G.R.Gladstone et al.