Jupiter Dynamo?
A recent paper in Nature Communications “A complex dynamo inferred from the hemispheric dichotomy of Jupiters magnetic field”, Moore, K. M. et al. begins by stating that Jupiter’s magnetic field is generated by a dynamo in its interior, but adds “we find that Jupiter’s magnetic field is different from all other known planetary magnetic fields”. The authors claim that although Jupiter’s magnetic field is primarily a dipole the magnetic field in the northern hemisphere (Figure 1 a) displays more of a “non-dipole field” than in the southern hemisphere “with most of the flux emerging from the ‘dynamo’ region in a narrow band in the northern hemisphere, some of which “returns through an intense isolated patch near the equator”. The authors calculate the fields in Figure 1b stating it is the field at 90% of the radius of the planet, that is, 7,000 km below the surface. However, this ‘downward continuation’ of the currently measured field at high elevations assumes there are no field sources between the satellite orbit and the surface of the planet, which is not true on Jupiter.
One reason there is more detail in the northern hemisphere is that Juno’s first pass (PJ1) was closer to the north (35,000-km) than the south pole (70,000-km) and due to the precession of the orbit (Figure 2) the perijove (closest point in each orbit) is now (9/7/2018) at 16.6° N Lat. The elevations of the orbit above the poles has been too great to detect the particles which produce the powerful auroral ovals.
Cyclic Catastrophism
As explained in a number of posts on this site, the magnetic fields of the giant planets are completely different from the Earth’s. Jupiter’s magnetic field is generated by a powerful stream (1032/s) of low mass, doubly charged ions called helions ( 3Ne++) circling Jupiter prograde at 17,800 km/s (yellow in Figure 3). The external magnetic field of Jupiter is sixty times more powerful than the field of the Earth because the particles generating it are in space, not shielded by the solid planet. The particles are continuously being generated by a ‘fusion furnace’ at the center of a 6,000-year old impact crater on the surface of Jupiter some 50,000 km east of the Great Red Spot fusing vast amounts of deuterium and protons (D + P -> 3Ne++ + 4.98 MeV) that comprise the solid Methane Gas Hydrate planet.

Fig. 3. Helion streams which produce Jupiter’s magnetic field are yellow. Blue are the vortical streams deflected to the poles which produce the auroral ovals.
The helions’ high velocities and the rapid revolution of Jupiter combine to form a helion vortex which exits the atmosphere forming the Great Red Spot. The stream then combines with the powerful stream of helions circling the planet near the equator, currently believed to be a dangerous nuisance called the ‘Inner Radiation Belt’. The belt was originally thought to comprise electrons, but the Juno JEDI instrument has found that it comprises positive ions. JEDI was not able to identify the helions or determine the direction of their motion because their velocity is too high, therefore NASA scientists assume the particles in the ‘radiation belt’ are ‘mirroring’, travelling both prograde and retrograde as in radiation belts of the Earth.
Above the Great Red Spot, two streams of helions are deflected toward the north and south poles where their powerful impacts produce the constant auroral ovals (blue in Figure 3).
A previous presentation by John Connerney of NASA provided a video of the same magnetic field as the cited paper, which also includes the cloud features on Jupiter. Comparison of the video with Figure 4. shows that the anomalous magnetic field described in the cited article as magnetiic flux “returns through an intense isolated patch near the equator” is due to the deflection of the counter-clockwise helion motion at the northern edge of the Great Red Spot by an eastward jet stream which produces the turbulence on the northwest . . THis comparison shows that the north edge of the Great Red Spot collides with the eastward jet stream, resulting in a large zone of turbulence to its northwest. This causes a clockwise swirling of the helions at that point, sensed by the MAG instrument as a reversed magnetic field. The main counter-clockwise stream of invisible helions goes upward and impacts the inner belt above the Great Red Spot.
The reduction of the diameter and intensity of the Great Red Spot over the lifetime of the Juno mission 800-days is evidence of the decrease in the power of the fusion reaction and can more accurately be determined by a decline in the strength of Jupiter’s magnetic field during that period. If NASA compares the total magnetic field data from the first Juno pass with the most recent values they will find this decrease and will have to add this to the long list of unexplained observations..