Unlike other planets, Saturn’s upper winds prove to provide ‘fuel’ to drive powerful auroras

Scientists have long wondered that some of Saturn’s auroras arise from cyclones in the atmosphere. After all, on Earth or other planets like Jupiter, auroras come from charged particles interacting with the magnetosphere. A team from the University of Leicester has recently discovered an unprecedented mechanism that suggests that strong winds in the upper reaches of Saturn’s north pole are responsible for fueling Saturn’s auroras.

The Pioneer 11 spacecraft first saw signs of Saturn’s auroras when it flew by Saturn in 1979; Voyager 1 and Voyager 2 flybys of Saturn in the early 1980s also provided observations of the giant magnetic bubble around Saturn, just like Earth , Saturn’s magnetosphere interacts with the solar wind to form the auroras.

The magnetosphere isn’t the only driving force behind Saturn’s auroras, however, and Saturn is a unique planet so far observed in that some of the auroras are produced by winds in Saturn’s own atmosphere.

When the Cassini probe set out to measure the overall rotational speed by measuring radio-emission pulses from Saturn’s atmosphere, it was astonished to find that Saturn’s rotational rate had changed over 20 years, and that Saturn’s rotational period would drift eerily north-south and at different speeds in different seasons. rotate. We determined that the internal rotation rate of Saturn must remain constant, so there must be other mechanisms outside affecting the observations.

So far, various theories trying to explain changes in Saturn’s magnetic field have surfaced, such as Saturn’s rings, the methane atmosphere of Titan, and the eruption of Enceladus’ volcanoes, etc., but none of the above seems to be correct.

New research by a team from the University of Leicester has detected winds in the planet’s upper atmosphere for the first time and provides evidence that these winds are what tug on Saturn’s magnetic field and provide the ‘fuel’ to produce the auroras. Dragging the planet’s magnetic field so that the latter keeps changing makes it impossible for scientists to measure the speed of Saturn’s rotation or to know how long Saturn’s day is (but then scientists figured out a way to measure Saturn’s rotation period using Saturn’s ring system).

The researchers believe that the system is driven by the energy of Saturn’s thermosphere, and the ionospheric wind speed falls between 0.3 and 3 kilometers per second, determining the origin of the radio pulse variation and dispelling our confusion about the variation of Saturn’s rotation speed.

The new paper is published in the journal Geophysical Research Letters.

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