Jupiter's aurora presents a powerful mystery

September 6, 2017
This is a reconstructed view of Jupiter's northern lights through the filters of the Juno Ultraviolet Imaging Spectrograph instrument on Dec. 11, 2016, as the Juno spacecraft approached Jupiter, passed over its poles, and plunged towards the equator. Credit: NASA/JPL-Caltech/Bertrand Bonfond

Scientists on NASA's Juno mission have observed massive amounts of energy swirling over Jupiter's polar regions that contribute to the giant planet's powerful aurora - only not in ways the researchers expected.

Examining data collected by the ultraviolet spectrograph and energetic-particle detector instruments aboard the Jupiter-orbiting Juno spacecraft, a team led by Barry Mauk of the Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, observed signatures of powerful electric potentials, aligned with Jupiter's magnetic field, that accelerate electrons toward the Jovian atmosphere at energies up to 400,000 electron volts. This is 10 to 30 times higher than the largest auroral potentials observed at Earth, where only several thousands of volts are typically needed to generate the most intense —known as discrete aurora—the dazzling, twisting, snake-like northern and southern lights seen in places like Alaska and Canada, northern Europe, and many other northern and southern .

Jupiter has the most powerful aurora in the solar system, so the team was not surprised that electric potentials play a role in their generation. What's puzzling the researchers, Mauk said, is that despite the magnitudes of these potentials at Jupiter, they are observed only sometimes and are not the source of the most intense auroras, as they are at Earth.

This image, created with data from Juno's Ultraviolet Imaging Spectrograph, marks the path of Juno's readings of Jupiter's aurora, highlighting the electron measurements that show the discovery of the so-called discrete auroral acceleration processes indicated by the "inverted Vs" in the lower panel. Credit: NASA/JPL-Caltech/SwRI/Randy Gladstone

"At Jupiter, the brightest auroras are caused by some kind of turbulent acceleration process that we do not understand very well," said Mauk, who leads the investigation team for the APL-built Jupiter Energetic Particle Detector Instrument (JEDI). "There are hints in our latest data indicating that as the power density of the auroral generation becomes stronger and stronger, the process becomes unstable and a new acceleration process takes over. But we'll have to keep looking at the data."

Scientists consider Jupiter to be a physics lab of sorts for worlds beyond our solar system, saying the ability of Jupiter to accelerate charged particles to immense energies has implications for how more distant astrophysical systems accelerate particles. But what they learn about the forces driving Jupiter's aurora and shaping its space weather environment also has practical implications in our own planetary backyard.

"The highest energies that we are observing within Jupiter's auroral regions are formidable. These energetic particles that create the aurora are part of the story in understanding Jupiter's radiation belts, which pose such a challenge to Juno and to upcoming spacecraft missions to Jupiter under development," said Mauk. "Engineering around the debilitating effects of radiation has always been a challenge to spacecraft engineers for missions at Earth and elsewhere in the solar system. What we learn here, and from spacecraft like NASA's Van Allen Probes and Magnetospheric Multiscale mission (MMS) that are exploring Earth's magnetosphere, will teach us a lot about space weather and protecting spacecraft and astronauts in harsh space environments. Comparing the processes at Jupiter and Earth is incredibly valuable in testing our ideas of how planetary physics works."

Juno global auroral image (Image 1) combined with electron measurements showing the discovery at Jupiter of the so-called discrete auroral acceleration process indicated by the “inverted V’s”, in the upper right panel (keV is short for kilo-electron-volts). This signature indicates the presence of powerful magnetic field-aligned electric potentials (lower right) that accelerate electrons towards the atmosphere to energies that are more than an order of magnitude greater than any observed at Earth. Credit: G. Randy Gladstone

Mauk and colleagues present their findings in the Sept. 7 issue of the journal Nature.

Explore further: NASA's Juno and JEDI prepare to unlock the mysteries of Jupiter

More information: B. H. Mauk et al. Discrete and broadband electron acceleration in Jupiter's powerful aurora, Nature (2017). DOI: 10.1038/nature23648

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Chris_Reeve
1 / 5 (7) Sep 06, 2017
If your plasma model works for the Earth, but not Jupiter, then you are missing something fundamental about plasmas ...
cantdrive85
1.7 / 5 (6) Sep 06, 2017
"At Jupiter, the brightest auroras are caused by some kind of turbulent acceleration process that we do not understand very well,"

At least they are honest about their ignorance of double layers, Birkeland Currents, electric fields, and other ubiquitous phenomena of plasma physics.
observed signatures of powerful electric potentials, aligned with Jupiter's magnetic field, that accelerate electrons toward the Jovian atmosphere at energies up to 400,000 electron volts.

There are clues to be had here, it should be blatantly obvious there are powerful electric fields involved.
Whydening Gyre
5 / 5 (3) Sep 07, 2017
entirely different chemical makeup and (gravity derived) densities of the Jovian atmosphere...
Electrical potentials are side-effect...
CD,
I think something about what CR posted applies to your perceptions on electricity's importance...
cantdrive85
2.6 / 5 (5) Sep 07, 2017
WG, the horse leads the cart, not the other way around. I your case, the brush spreads the paint, it is not the paint that moves the brush.
Chris_Reeve
1 / 5 (6) Sep 07, 2017
From Anthony Peratt's Physics of the Plasma Universe

"Consider a cosmic plasma ne = 103 m−3, E = 10−6 V/m, and T = 3 keV. For these values, electrons with energies greater than 0.5 μeV will run away. Thus, electrons in cosmic plasmas are readily accelerated to high energies in the presence of even very small electric fields.

Equation (4.22), and the runaway process, will be modified if a magnetic induction B is present. However, if E and B are parallel, the runaway condition is not altered. In addition, the body of electron population which attracts electrons of less than runaway speed is eroded by the escape of electrons brought up to critical speed. If the electric field persists long enough, all the electrons will eventually run away in energy."

Peratt then goes on to discuss runaway charged particles as the source of cosmic rays and of charge particle flux from supernova. It appears that Perattt may have already staked a claim in an answer to this mystery.
Chris_Reeve
1 / 5 (6) Sep 07, 2017
This section of the text can be read online at ...

https://books.goo...;f=false

Equation (4.22) is simply "The equation of motion of an electron in a region of plasma in which there is an external electric field E".

Thus, it seems that there is possibly some irony here in that the admitted confusion of the astrophysicists on why these electrons appear unexpectedly accelerated may fundamentally relate to their refusal to consider that these same sort of cosmic E-fields can also act as the source for the very high energy cosmic rays which they also label a mystery.
f_darwin
1 / 5 (3) Sep 09, 2017
There is no mystery. as I have pointed many times before to space agencies and their web pages. Jupiter planetary evolution is becoming a proto-sun. in future Earth will be a double star system. Man do not know structure of mater or space bodies evolution. Juno only served man's curiosity re-inventing the wheel. NASA knows all information was available on official request past 42 years. MG1
Whydening Gyre
5 / 5 (2) Sep 09, 2017
WG, the horse leads the cart, not the other way around. I your case, the brush spreads the paint, it is not the paint that moves the brush.

Very gracious retort..
However, it is where I want to put the paint that drives both the paint AND brush...:-)
Maggnus
5 / 5 (6) Sep 09, 2017
There is no mystery. as I have pointed many times before to space agencies and their web pages. Jupiter planetary evolution is becoming a proto-sun. in future Earth will be a double star system. Man do not know structure of mater or space bodies evolution. Juno only served man's curiosity re-inventing the wheel. NASA knows all information was available on official request past 42 years. MG1

QUACK! Quack quack quack quack....
Maggnus
5 / 5 (5) Sep 09, 2017
Thus, it seems that there is possibly some irony here in that the admitted confusion of the astrophysicists on why these electrons appear unexpectedly accelerated may fundamentally relate to their refusal to consider that these same sort of cosmic E-fields can also act as the source for the very high energy cosmic rays which they also label a mystery.
More correctly, the supposed driver laid out by the Cult of Bolts has been found to be physically untenable and without merit, thus leading to the increasingly tedious screeching of the Acolytes of the Cult.
cantdrive85
1 / 5 (3) Sep 09, 2017
However, it is where I want to put the paint that drives both the paint AND brush...:-)

Just as the EM fields decides where/how the electrons go, not gravity.
Whydening Gyre
5 / 5 (4) Sep 10, 2017
However, it is where I want to put the paint that drives both the paint AND brush...:-)

Just as the EM fields decides where/how the electrons go, not gravity.

Really?
And just what decides where the EM fields are?
Gravitationally collected Matter, maybe...?
RealityCheck
1 / 5 (3) Sep 10, 2017
@Whyde.
...what decides where the EM fields are?
Gravitationally collected Matter, maybe...?
E-M field exists everywhere; and first fundamental particles (according to SM) were 'charged particle' Quarks as part of a high-energy Quark-Gluon PLASMA. Said Quarks aggregate into charged Protons, alongside charged Electrons, together forming a plasma of its own type/dynamics spread 'almost uniformly' across space with little density gradients between neighboring regions of space. It wasn't until sufficient proton-electron plasma 'aggregated/concentrated' sufficient MASS-ENERGY via E-M charge-interaction/plasmoid phenomena etc, and especially 'seeded' with some 'neutral charge' cotents, that GRAVITY effectiveness became a 'player' in FURTHER aggregation concentration. With more mass-energy concentration/accumulation came more CUMULATIVE gravity STRENGTH, and the rest is, as they say, 'history' as observed all around us. Cheers. :)
Whydening Gyre
5 / 5 (2) Sep 10, 2017
@Whyde.
E-M field exists everywhere;

At differing intensities.
and first fundamental particles (according to SM) were 'charged particle' Quarks as part of a high-energy Quark-Gluon PLASMA.

And... what characteristic makes it "Charged"?
Said Quarks aggregate into charged Protons,

How...?
alongside charged Electrons, together forming a plasma of its own type/dynamics spread 'almost uniformly' across space with little density gradients between neighboring regions of space.

You've described Hydrogen. With insufficient "charge" (density) to aggregate. Only unlike charges attract. And... Originally all the same, ergo, repelling.
It wasn't until sufficient proton-electron plasma 'aggregated/concentrated' sufficient MASS-ENERGY via E-M charge-interaction/plasmoid phenomena etc,

Remember - like charges repel... Something else had to initiate aggregation.
You "theory" is missing one important component. Think about it...
Whydening Gyre
5 / 5 (2) Sep 10, 2017
@Whyde;
... and especially 'seeded' with some 'neutral charge' contents,

And.... where did those come from....?
that GRAVITY effectiveness became a 'player' in FURTHER aggregation concentration. With more mass-energy concentration/accumulation came more CUMULATIVE gravity STRENGTH, and the rest is, as they say, 'history' as observed all around us. Cheers. :)

I don't entirely agree with your "timeline".
I believe it has more to do with volumetric scales and ratios. You know, the easy stuff...
RealityCheck
1 / 5 (4) Sep 11, 2017
@Whyde.
At differing intensities.
The E-M field itself is fundamentally ubiquitously/uniformly distributed; even when Quantum Chaos 'fluctuations' perturb this field, it remains essentially 'isometric/isotropic' everywhere UNTIL a LOCAL CHARGED perturbation produces a PERSISTENT SOLITONIC feature which we call 'particle' (be it fundamental Quark or more evolved Protons/Electrons.
what characteristic makes it "Charged"?
The Standard Model does not address/explain cause/source of fundamental 'charge' property.
How...?
Again, the Standard Model doesn't say.
You've described Hydrogen.
No, I described a PLASMA consisting of + and - charged particles. Ionized Hydrogen is a +Proton particle; Electron is -charge.
Remember - like charges repel...
And Unlike attract. So?
Something else had to initiate aggregation. You "theory"..
What "my theory"? I spoke only according to current Standard Model/Big Bang 'understandings' and 'concepts'.

cont.
RealityCheck
1 / 5 (4) Sep 11, 2017
Reformat Quotes:
At differing intensities.
The E-M field itself is fundamentally ubiquitously/uniformly distributed; even when Quantum Chaos 'fluctuations' perturb this field, it remains essentially 'isometric/isotropic' everywhere UNTIL a LOCAL CHARGED perturbation produces a PERSISTENT SOLITONIC feature which we call 'particle' (be it fundamental Quark or more evolved Protons/Electrons.
what characteristic makes it "Charged"?
The Standard Model does not address/explain cause/source of fundamental 'charge' property.
How...?
Again, the Standard Model doesn't say.
You've described Hydrogen.
No, I described a PLASMA consisting of + and - charged particles. Ionized Hydrogen is a +Proton particle; Electron is -charge.
Remember - like charges repel...
And Unlike attract. So?
Something else had to initiate aggregation. You "theory"..
What "my theory"? I spoke only according to current Standard Model/Big Bang 'understandings' and 'concepts'.

con
RealityCheck
1 / 5 (3) Sep 11, 2017
@Whyde continued:
@Whyde... and especially 'seeded' with some 'neutral charge' contents,
And.... where did those come from....?
The Standard Model says they arise when "universe expanded and cooled" to allow Combination of +Hydrogen nuclei (+proton particles) and -Electron particles.
that GRAVITY effectiveness became a 'player' in FURTHER aggregation concentration. With more mass-energy concentration/accumulation came more CUMULATIVE gravity STRENGTH, and the rest is, as they say, 'history' as observed all around us.
I don't entirely agree with your "timeline".
I believe it has more to do with volumetric scales and ratios. You know, the easy stuff...
The 'timeline' and 'volumetric' and 'scales/ratios' are as indicated/claimed by The Standard Model. So you disagree with that too? Great. Maybe you should construct your own ToE; or, if you already have, since you disagree with Standard Model, maybe you could post it for my benefit.

Thanks, Whyde. :)
Whydening Gyre
5 / 5 (2) Sep 12, 2017
...
that GRAVITY effectiveness became a 'player' in FURTHER aggregation concentration. With more mass-energy concentration/accumulation came more CUMULATIVE gravity STRENGTH, and the rest is, as they say, 'history' as observed all around us.
I don't entirely agree with your "timeline".
I believe it has more to do with volumetric scales and ratios. You know, the easy stuff...
The 'timeline' and 'volumetric' and 'scales/ratios' are as indicated/claimed by The Standard Model. So you disagree with that too?Maybe you should construct your own ToE; or, if you already have, since you disagree with Standard Model, maybe you could post it for my benefit.

1 clue - spin momentum...
RealityCheck
1 / 5 (2) Sep 12, 2017
@Whyde.
... that GRAVITY effectiveness became a 'player' in FURTHER aggregation concentration. With more mass-energy concentration/accumulation came more CUMULATIVE gravity STRENGTH, and the rest is, as they say, 'history' as observed all around us.
I don't entirely agree with your "timeline".
I believe it has more to do with volumetric scales and ratios. You know, the easy stuff...
The 'timeline' and 'volumetric' and 'scales/ratios' are as indicated/claimed by The Standard Model. So you disagree with that too?Maybe you should construct your own ToE; or, if you already have, since you disagree with Standard Model, maybe you could post it for my benefit.

1 clue - spin momentum...
Are you using "spin momentum" to mean "angular momentum"? Or do you make some effective, physically meaningful, distinction between these two in your own 'ToE', Whyde?
Whydening Gyre
5 / 5 (1) Sep 12, 2017
1 clue - spin momentum...

Are you using "spin momentum" to mean "angular momentum"?

Since they are both a result of the same underlying mechanic (but at vastly different scales) and can be considered opposites within that mechanical context, you can use either (dependent on your perspective context)
Or do you make some effective, physically meaningful, distinction between these two in your own 'ToE', Whyde?

Don't believe in "ToE"s. They're like opinions, and can change at the drop of a hat.
I rather prefer - "Best guess given the data available..."
RealityCheck
1 / 5 (2) Sep 13, 2017
@Whyde.
From @Whyde: 1 clue - spin momentum...
From @RealityCheck: Are you using "spin momentum" to mean "angular momentum"?
From @Whyde: Since they are both a result of the same underlying mechanic (but at vastly different scales) and can be considered opposites within that mechanical context, you can use either (dependent on your perspective context)
OK, mate; thanks for your clarification. :)
From @RealityCheck: Or do you make some effective, physically meaningful, distinction between these two in your own 'ToE', Whyde?
From @Whyde: Don't believe in "ToE"s. They're like opinions, and can change at the drop of a hat. I rather prefer - "Best guess given the data available..."
OK again, thanks mate.

Now that you have clarified your meanings re those things, can you now proceed to elaborate what your "clue" itself implies in your own "best guess" perspective on the relevant phenomena? :)
Whydening Gyre
5 / 5 (1) Sep 13, 2017
...
Now that you have clarified your meanings re those things, can you now proceed to elaborate what your "clue" itself implies in your own "best guess" perspective on the relevant phenomena? :)

The fields, themselves, are in spin...
RealityCheck
1 / 5 (2) Sep 15, 2017
@Whyde.
...
Now that you have clarified your meanings re those things, can you now proceed to elaborate what your "clue" itself implies in your own "best guess" perspective on the relevant phenomena? :)

The fields, themselves, are in spin...
Thanks. Can you please explain what 'physical energy-space system' and/or 'abstract analytical frame of reference' such fields' spin is relative to?
Whydening Gyre
5 / 5 (1) Sep 18, 2017
@Whyde.
...
Now that you have clarified your meanings re those things, can you now proceed to elaborate what your "clue" itself implies in your own "best guess" perspective on the relevant phenomena? :)

The fields, themselves, are in spin...
Thanks. Can you please explain what 'physical energy-space system' and/or 'abstract analytical frame of reference' such fields' spin is relative to?

I dunno, RC... Your soundin' like a potential "plagiarist"...:-)
RealityCheck
1 / 5 (2) Sep 19, 2017
@Whyde.
@Whyde.
Now that you have clarified your meanings re those things, can you now proceed to elaborate what your "clue" itself implies in your own "best guess" perspective on the relevant phenomena? :)
The fields, themselves, are in spin
Thanks. Can you please explain what 'physical energy-space system' and/or 'abstract analytical frame of reference' such fields' spin is relative to?
I dunno, RC... Your soundin' like a potential "plagiarist"...:-)
Hahaha! Good one, mate! I see what you're alluding to there. Well played! ;-)

But rest assured I am way ahead of you, so you won't be divulging anything which my now-completed ToE theorizing process hasn't already considered/accepted/rejected according to the objective reality-referential observations-and-logics-train involved in that process.

Anyhow, please do not feel compelled to satisfy my query. I only asked to be polite and interested in your perspective (as I have been in all others). Cheers. :)
Whydening Gyre
5 / 5 (1) Sep 19, 2017
Hahaha! Good one, mate! I see what you're alluding to there. Well played! ;-)

But rest assured I am way ahead of you

Careful, now... Your ego is showing...
so you won't be divulging anything which my now-completed ToE

I don't necessartily agree, but -Does that mean you're gonna send me a copy now?
theorizing process hasn't already considered/accepted/rejected according to the objective reality-referential observations-and-logics-train involved in that process.

My grandson LOVES observing trains...
Anyhow, please do not feel compelled to satisfy my query. I only asked to be polite and interested in your perspective (as I have been in all others). Cheers. :)

Remember... One man's ToE is another man's bar to beat...
(And we're a pretty tenacious bunch...)
And, that said - vortexes (spin). Differences of potential giving rise to physical interactions.
Nothing - and ALMOST nothing...
RealityCheck
1 / 5 (3) Sep 20, 2017
@Whyde.
ego is showing
Not at all; just observing our respective offerings vis-a-vis comprehending/explaining the universal physical reality; ie: recent mainstream discoveries/reviews in cosmo/astro/quantum physics are increasingly confirming me correct all along on many fronts/issues; can you claim likewise?
Does that mean you're gonna send me a copy now?
As soon as I've finalized my reality-based-axiom 'Maths' to 'model' it, then anyone may see a 'copy' of my reality-based-postulate 'ToE' on line.
My grandson LOVES observing trains
When he progresses to the stage that his 'observation' also encompasses the TRACKS on which they run, then he'll be 'on track' to comprehending the 'wider phenomena set'.
One man's ToE is another man's bar to beat
Go for it, mate! - vortexes (spin). Differences of potential giving rise to physical interactions. Nothing - and ALMOST nothing. FYI, mate: "Nothingness Potential" not real; "Direction Potential" is. :)
RealityCheck
1 / 5 (3) Sep 20, 2017
@Whyde.
ego is showing
Not at all; just observing our respective offerings vis-a-vis comprehending/explaining the universal physical reality; ie: recent mainstream discoveries/reviews in cosmo/astro/quantum physics are increasingly confirming me correct all along on many fronts/issues; can you claim likewise?
Does that mean you're gonna send me a copy now?
As soon as I've finalized my reality-based-axiom 'Maths' to 'model' it, then anyone may see a 'copy' of my reality-based-postulate 'ToE' on line.
My grandson LOVES observing trains
When he progresses to the stage that his 'observation' also encompasses the TRACKS on which they run, then he'll be 'on track' to comprehending the 'wider phenomena set'.
One man's ToE is another man's bar to beat
Go for it, mate!
- vortexes (spin). Differences of potential giving rise to physical interactions. Nothing - and ALMOST nothing.
FYI, @Whyde: "Nothingness Potential" not real; "Direction Potential" is real. :)
RealityCheck
1 / 5 (2) Sep 20, 2017
PS, @Whyde: I had to repost that because the time limit for editing expired; apologies for any inconvenience caused, mate. :)
cantdrive85
1 / 5 (2) Sep 24, 2017
Jupiter as part of the Sun's circuit;
https://youtu.be/pitwnMK-RxU

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