Spacecraft orbiting in the 'Safe Zone', between two and three Earth radii, can be subjected to high levels of harmful radiation as the radiation belts fluctuate in response to space weather events.
NOTE: This visualization shows the Earth's magnetic dipole field lines rotating rigidly with the Earth. Technically, this is inaccurate. Ions and electrons in the lower atmosphere can create currents which can make these lines 'drag' with Earth's rotation, but this will occur mostly near the Earth and not higher up. More details on this process can be found in the FAQ at the The Exploration of the Earth's Magnetosphere web site, Does the Earth's magnetic field rotate?.
Here a satellites orbit is well within the Safe Zone. Only the outer belt is visible at this time. The inner belt is too faint to be distinguished on this data scale.
Later still, the Safe Zone re-opens. The inner belts have not yet shed the high-energy electrons from the event and so their enhanced electron flux makes them visible on this data scale.