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Saturn's Aurora

Saturn's aurora behaviors are considered unique.

Saturn has its own unique brand of aurora that lights up the polar cap, unlike any other planetary aurora known in our solar system. This odd aurora revealed itself to one of the infrared instruments on NASA's Cassini spacecraft.

Here is relevant information from Wikipedia:
The magnetosphere of Saturn is the cavity created in the flow of the solar wind by the planet's internally generated magnetic field. Saturn's magnetosphere is the second largest of any planet in the Solar System after Jupiter. The magnetopause, the boundary between Saturn's magnetosphere and the solar wind, is located at a distance of about 20 Saturn radii from the planet's center, while its magnetotail stretches hundreds of Saturn radii behind it.

Saturn's magnetosphere is filled with plasmas originating from both the planet and its moons. The main source is the small moon Enceladus, which ejects as much as 1,000 kg/s of water vapor from the geysers on its south pole, a portion of which is ionized and forced to co-rotate with the Saturn's magnetic field. This loads the field with as much as 100 kg of water group ions per second. This plasma gradually moves out from the inner magnetosphere via the interchange instability mechanism and then escapes through the magnetotail.

The interaction between Saturn's magnetosphere and the solar wind generates bright oval aurorae around the planet's poles observed in visible, infrared and ultraviolet light. The aurorae are related to the powerful saturnian kilometric radiation (SKR), which spans the frequency interval between 100 kHz to 1300 kHz and was once thought to modulate with a period equal to the planet's rotation. However, later measurements showed that the periodicity of the SKR's modulation varies by as much as 1%, and so probably does not exactly coincide with Saturn's true rotational period, which as of 2010 remains unknown. Inside the magnetosphere there are radiation belts, which house particles with energy as high as tens of megaelectronvolts. The energetic particles have significant influence on the surfaces of inner icy moons of Saturn.

My comment:

Could the 'internally generated magnetic field' be partially generated by an external electric current, as part of a circuit with the Sun? I know of no measurement of such a current (why would anyone look?). Any magnetic field comes from an electric current.

Instead the external solar wind, which has a variable flow of its charged particles, is assumed primarily responsible for the magnetosphere.

The uncertain 'true rotational period' was the topic of a post to EUT on 09/09/2019.

Other observations with Saturn's aurora:

From an online story titled 'Saturn's Aurora Heartbeat Discovered':

Saturn's aurora, a ghostly ultraviolet glow that illuminates the gas giant's upper atmosphere near the poles, has a heartbeat that pulses in tandem with the planet's radio emissions, scientists have discovered.

The pulsing auroras on Saturn occur about once every 11 Earth hours or so ? the length of one day on the ringed planet, researchers found.

"This is an important discovery for two reasons," said study leader Jonathan Nichols of the University of Leicester in England. "First, it provides a long-suspected but hitherto missing link between the radio and auroral emissions, and second, it adds a critical tool in diagnosing the cause of Saturn's irregular heartbeat."

A previous (September 9, 2019) post on EUT titled Saturn Rotation period' described Saturn's radio emissions and its interior.
The fluctuations in radio were treated as the indicating the rotation period of that hemisphere. This story connects the radio fluctuations to pulses in the aurora. The Sun is not mentioned with this radio fluctuation.

From an online story titled: 'Auroral Processes Associated With Saturn's Moon Enceladus'
We show that the interaction of the [Encedelas] plume with Saturn's corotating magnetospheric plasma leads to a wide variety of effects, including strong local distortions of the planetary magnetic field,
the acceleration of electron beams, the generation of whistler mode radio emissions, and the excitation of a standing Alfvén wave that links Enceladus to Saturn's upper atmosphere. Many of these effects are similar to those observed near Jupiter's moon Io, which is known to produce auroral emissions near the foot of its magnetic
flux tube, and to those occurring in the Earth's aurora.

Although the RPWS instrument was designed to detect radio and plasma waves, the intense noise on the right side of the spectrogram is caused by dust particles striking the spacecraft. Because the spacecraft is moving at a very high velocity, about 17 km/s, relative to Enceladus (and to the dust particles), when a small particle strikes the spacecraft, it is instantly vaporized and ionized, thereby causing a rapidly expanding cloud of hot electrons that produces a voltage pulse on the RPWS electric antenna.

Just what causes these relatively large downstream magnetic field fluctuations is not known for certain. Pryor et al. suggested that they may be caused by Alfvén waves that are reflecting back and forth between the two hemispheres in the downstream region. However, they are also reminiscent of a downstream flow instability, such as the Kármán vortex street commonly seen downstream of a cylindrical object in a hydrodynamic flow.

The cause of these fluctuations is uncertain. Perhaps a new probe to Saturn is needed for progress.
I just checked for NASA future missions to the planet Saturn but there are none.
I discovered only this:
Dragonfly] will launch in 2026, but won't reach Titan until the 2034 because Saturn is so far from us.
Dragonfly will also explore Titan's atmosphere, surface properties, subsurface ocean and liquid on the surface.

This 2034 probe's mission might offer little new data on Saturn or any of its other moons.

Of course Saturn's aurora is generated by electrical activity, relevant to EUT.


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