6
$\begingroup$

As of May 2024, Earth was just hit by a quite strong solar storm, lighting up the skies with auroras even in areas as far from the polar regions as Ushuaia, Coimbra or Northern California.

We often see discussed the potential for such episodes of strengthened solar winds, like Coronal Mass Ejections, to disrupt communications and the power-grids on Earth, perhaps even threatening civilization itself. The largest such event in recorded history was the Carrington Event. Back then human society didn't rely a lot on electronics, but yet there was reports of telegraph lines melting due to induced currents:

"In 1859, the first and most powerful solar flare ever observed occurred, known as the Carrington event. Within a couple of days of the flare, the Earth’s magnetic field oscillated wildly from the magnetized plasma thrown toward us. The magnetic field lines of the Earth bounced back and forth across telegraph wires, causing massive failures and even melted wires from the induced currents." - source

That begs the question, the same way solar plasma pushing against Earth's magnetic field can melt wires close to the surface, can it also induce or mess with currents down into the Earth core, that behaves like a giant conductor, whose currents generate this very magnetic field?

According to wikipedia, near the Earth's orbit at 1 astronomical unit (AU) the solar plasma flows at speeds ranging from 250 to 750 km/s with a density ranging between 3 and 10 particles (mostly hydrogen ions) per cubic centimeter. Earth's magnetic field is able to trap particles from the solar wind into Van Allen radiation belt that extends up to 60.000 km from Earth, so I believe the kinetic energy of plasma going through a circular section this wide gives sort of an upper bound to the amount of energy hypothetically available for exchange, that I tried to estimate as follows, taking mean values:

enter image description here

This estimate of 7 terawatts of mean solar wind power intercepted by Earth's magnetic field is quite large, despite the low average density of the solar wind, a few atoms per cubic centimeter. For comparison, the estimates for total geothermal power dissipated by the whole planet is about 47 terawatts, not that far, perhaps can be surpassed by a large storm like the one happening now.

So I wonder, even if Earth's core captures only a small amount of this energy flow as induced currents, if on timescales of billions of years this can have significant impact on Earth's geology.

$\endgroup$
5
  • 4
    $\begingroup$ I was going to add a bounty but then wondered if the Astronomy SE community is really the best source for authoritative answers to this particular question. Did you consider asking in Earth Science SE? It's certainly 100% on-topic in both sites. If I add a bounty here, then the question can't be migrated for eight days. If you flag for moderator assistance and ask to have this migrated there, I can bounty it there. Bottom line: If you are comfortable staying here then I'll bounty here. $\endgroup$
    – uhoh
    May 13 at 22:19
  • 1
    $\begingroup$ Thank you, @uhoh , I added a bounty myself here. If it doesn't work here we can try in Earth Science. $\endgroup$
    – ksousa
    May 13 at 22:33
  • 1
    $\begingroup$ Earth receives from Sun around 160.000TW of electrical energy in form of electromagnetic radiation - which also cause atmospheric ionization, induction of ring currents etc. Geology itself is not driven by the magnetic core, but by the heat and heat flux flux (I'm curious to learn otherwise). Thus while I expect a negative answer it's still difficult to dismiss and the devil might be in the details. $\endgroup$ May 15 at 6:41
  • $\begingroup$ @planetmaker, I believe most of these 160.000TW are rerradiated back to space, from atmosphere and outer surface. $\endgroup$
    – ksousa
    yesterday
  • $\begingroup$ Sure. Yet a meagre 1% of that is still 250 times more than the 7TW overall you estimated for the magnetic storm. $\endgroup$ yesterday

1 Answer 1

0
$\begingroup$

If the earth's magnetic field extends into its core then charged particles from the sun bending earth's field will cause a small force in the core as charges in the core respond to a moved field line

New contributor
DaveTheWave is a new contributor to this site. Take care in asking for clarification, commenting, and answering. Check out our Code of Conduct.
$\endgroup$
1
  • $\begingroup$ Thank you for the observation, but I think this would better fit a comment. Not a proper answer. $\endgroup$
    – ksousa
    5 hours ago

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .