The Most Accurate Model Yet Of Jupiter's Bizarre Magnetic Field

It may look like a giant ball oozing with earthworms, but it's actually a simulation of Jupiter's massive and complex magnetosphere — a magnetic field that extends more than four million miles from its surface.

These models, which appear in the latest edition of Geophysical Research Letters, are surprisingly similar to Earth's, though on a much grander scale. Jupiter's magnetic field is 18,000 times more powerful than our own. Charged particles emanating from the sun are deflected around this magnetosphere, producing a cavity that's the second largest continuous structure in the solar system (the sun's heliosphere being the largest).

Writing in Wired, Adam Mann explains more:

The Earth generates a magnetic field by the convection of molten nickel-iron alloys in its outer core. Jupiter's outer core is also thought to be responsible for its enormous magnetic field, though it is liquid hydrogen crushed by intense pressure into a metallic form that generates the magnetism rather than iron compounds. In addition, the gas giant's surface is buffeted by powerful winds and huge storms, like the famous Great Red Spot. Scientists believe that these surface winds interact with the metallic liquid hydrogen below to stimulate some of the secondary properties of the magnetic field.

The Most Accurate Model Yet Of Jupiter's Bizarre Magnetic Field

But most previous models have tended to treat the upper winds and the metallic hydrogen separately, with researchers focusing on the dynamics of the core, which is largely responsible for the field. This has led to simulations of Jupiter's magnetic field that are either too strong, lopsided in one direction, or don't contain all the observed complexity of the actual field. The new analysis looks at how the upper layers influence the lower ones, using a more inclusive view of the planet's interior.

The researchers say it's the first true reproduction of the Jovian large scale magnetic field. They write:

Previous attempts to model Jupiter's interior dynamics have indeed largely failed to reproduce important features of the planet's large scale magnetic field. They were either too simplistic with a too strong dipolar component or they were restricted to the outer envelope dynamics producing a too axisymmetric and too little dipolar magnetic field. Here, the combination of a deep-seated dipolar dynamo and a magnetic banding associated with the equatorial jet is a key feature that distinguishes our model from these previous numerical attempts.

In addition to this, the researchers suspect that there are magnetic bands yet to be discovered. NASA's Juno mission will likely tell us more in 2016.

Check out Adam Mann's entire article at Wired. And read the entire study at the preprint journal arXiv: "Explaining Jupiter's magnetic field and equatorial jet dynamics."

Images: T. Gastine et. al./Geophysical Research Letters.

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