Jupiter

Jupiter has a magnetic field more than ten times stronger than that of Earth. The magnetosphere, which is created due to this field and its interaction with the solar wind, has major effects on the Jovian system. The size of the magnetosphere is larger than the Sun; since the innermost Jovian satellites are embedded deep in the magnetosphere, they are particularly affected by the magnetic field. One of the most complex results is the interaction of Io with this field.

Atoms such as sodium and sulfur have been discovered in a cloud around Io as it orbits Jupiter. This material is believed to originate on the surface of the satellite, and then reach space after being driven from the surface due to collisions with high energy particles. Through a not yet understood process, these atoms can become charged, and thus get trapped by the magnetic field of Jupiter. The result is a "plasma torus," a doughnut-shaped region of charged atoms, which rotates with the planet's magnetic field. Observations of these emissions in the ultraviolet since the 1970s have shown both a time variability and a spatial asymmetry in brightness from the torus.

Particles from the region around Io are also thought to be responsible for the aurora (similar to Earth's northern lights) seen at Jupiter's poles, but once again, the process is not clearly understood. The auroras appear to be caused by particles from the torus region, which rain down on the atmosphere at the poles of the planet, creating emissions.

Radio telescopes first detected emissions from Jupiter in the 1955. These radio waves are created when electrons travel through the planet's magnetosphere. Measurements show both short- and long-term variability of the radio emissions.