Wider and flatter than the Earth's magnetosphere, Jupiter's is stronger by an order of magnitude, while its magnetic moment is roughly 18,000 times larger.

Jupiter's internal magnetic field is generated by electrical currents in the planet's outer core, which is theorized to be composed of liquid metallic hydrogen.

[citation needed] The interaction of energetic particles with the surfaces of Jupiter's largest moons markedly affects their chemical and physical properties.

[10] The bulk of Jupiter's magnetic field, like Earth's, is generated by an internal dynamo supported by the circulation of a conducting fluid in its outer core.

[13][14][note 1] Jupiter's magnetic field rotates at the same speed as the region below its atmosphere, with a period of 9 h 55 m. No changes in its strength or structure had been observed since the first measurements were taken by the Pioneer spacecraft in the mid-1970s, until 2019.

[6] The distance from the magnetopause to the center of the planet is from 45 to 100 RJ (where RJ=71,492 km is the radius of Jupiter) at the subsolar point—the unfixed point on the surface at which the Sun would appear directly overhead to an observer.

[19] In front of the magnetopause (at a distance from 80 to 130 RJ from the planet's center) lies the bow shock, a wake-like disturbance in the solar wind caused by its collision with the magnetosphere.

[6] At the opposite side of the planet, the solar wind stretches Jupiter's magnetic field lines into a long, trailing magnetotail, which sometimes extends well beyond the orbit of Saturn.

[27] In the middle magnetosphere, at distances greater than 10 RJ from Jupiter, co-rotation gradually breaks down and the plasma begins to rotate more slowly than the planet.

[7] While Earth's magnetic field is roughly teardrop-shaped, Jupiter's is flatter, more closely resembling a disk, and "wobbles" periodically about its axis.

This current then flows radially away from the planet within the equatorial plasma sheet and finally returns to the planetary ionosphere from the outer reaches of the magnetosphere along the field lines connected to the poles.

[37] This highly hypothetical picture of the flux tube exchange was partly confirmed by the Galileo spacecraft, which detected regions of sharply reduced plasma density and increased field strength in the inner magnetosphere.

[40] The reconfiguration events usually included rapid and chaotic variation of the magnetic field strength and direction, as well as abrupt changes in the motion of the plasma, which often stopped co-rotating and began flowing outward.

[22] All these observations indicate that a solar wind driven reconnection process, known on Earth as the Dungey cycle, may also be taking place in the Jovian magnetosphere.

[50] As mentioned above, the main ovals are maintained by the strong influx of electrons accelerated by the electric potential drops between the magnetodisk plasma and the Jovian ionosphere.

[36] The precipitating electrons have energy in the range 10–100 keV and penetrate deep into the atmosphere of Jupiter, where they ionize and excite molecular hydrogen causing ultraviolet emission.

The spectrum of the auroral X-ray radiation consists of spectral lines of highly ionized oxygen and sulfur, which probably appear when energetic (hundreds of kiloelectronvolts) S and O ions precipitate into the polar atmosphere of Jupiter.

[60][note 4] The majority of these emissions are thought to be produced by a mechanism called "cyclotron maser instability", which develops close to the auroral regions.

In fact, the existence of Jupiter's rings was first hypothesized on the basis of data from the Pioneer 11 spacecraft, which detected a sharp drop in the number of high-energy ions close to the planet.

[71] Resonant interactions between the co-rotation and the particles' orbital motion has been used to explain the creation of Jupiter's innermost halo ring (located between 1.4 and 1.71 RJ).

[72] The particles originate in the main ring; however, when they drift toward Jupiter, their orbits are modified by the strong 3:2 Lorentz resonance located at 1.71 RJ, which increases their inclinations and eccentricities.

[67] The co-rotational flow of cold magnetospheric plasma is partially diverted around them by the currents induced in their ionospheres, creating wedge-shaped structures known as Alfvén wings.

Plasma originating from Io carries sulfur and sodium ions farther from the planet,[81] where they are implanted preferentially on the trailing hemispheres of Europa and Ganymede.

[69] Energetic electrons and ions, with the flux of the latter being more isotropic, bombard surface ice, sputtering atoms and molecules off and causing radiolysis of water and other chemical compounds.

[84] Oxidants produced by radiolysis, like oxygen and ozone, may be trapped inside the ice and carried downward to the oceans over geologic time intervals, thus serving as a possible energy source for life.

[85] As the DAM's spectrum extended up to 40 MHz, astronomers concluded that Jupiter must possess a magnetic field with a maximum strength of above 1 milliteslas (10 gauss).

[6] It received a radiation dosage one thousand times the lethal level for humans, the damage resulting in serious degradation of some high-resolution images of Io and Ganymede.

Several times electrical arcs occurred between rotating and non-rotating parts of the spacecraft, causing it to enter safe mode, which led to total loss of the data from the 16th, 18th and 33rd orbits.

The possibility was mooted of building a surface base on Callisto, because of the low radiation levels at the moon's distance from Jupiter and its geological stability.

...Juno revealed a planetary magnetic field rich in spatial variation, possibly due to a relatively large dynamo radius.