Using its magnetometer (MAG), Juno will create an extremely accurate and detailed three-dimensional map of Jupiter’s magnetic field. This unprecedented study will allow us to understand Jupiter’s internal structure and how the magnetic field is generated by the dynamo action inside – the churning of electrically charged material deep below the surface. MAG will also monitor the field for long-term variations, called secular variations, during the entire mission. Measurements of these variations, in combination with the map, will help us determine the depth of the dynamo region. Because Jupiter lacks a crust or continents that complicate the picture, Juno’s observations could be the most detailed ever of a planetary dynamo. Electrical currents can align themselves with the magnetic field, and these so-called Birkeland currents help drive the brilliant auroras around Jupiter’s poles. To better understand the auroras, MAG will measure these currents. MAG consists of the Flux Gate Magnetometer (FGM), which will measure the strength and direction of the magnetic field lines, and the Advanced Stellar Compass (ASC), which will monitor the orientation of the magnetometer sensors. Juno’s other instruments have their own small magnetic fields, and to avoid contamination, the MAG sensors sit as far from the rest of the spacecraft as possible. They are mounted on the magnetometer boom that sticks out from one of Juno’s solar arrays. As an extra precaution, there are two sets of MAG sensors – one 10 meters (33 feet) from the center of the spacecraft and one 12 meters (39 feet) from the center. By comparing measurements from both sensors, mission scientists can remove any contamination from the data. Dr. Jack Connerney of the NASA Goddard Space Flight Center (GSFC) leads the Magnetic Field Investigation. The FGM is provided by GSFC and the ASC is provided by Danish Technical University.