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Is there a way to induce a solar flare / coronal mass ejection (CME)?

For instance, could a very tight glob of charged particles reconfigure the the Sun's corona leading to this type of event? Is there a precedence for this type of glob in the experimental evidence or theory? What would be the characteristics of this glob?

Technology ranging from natural occurrence (a q-ball style answer -- though I doubt a q-ball could do this) up through moderate interstellar travel (the models we have on paper -- wormholes, Alcubierre drives, etc.). Preference is given to natural occurrences. The upper limit is nebulous.

I've seen a few questions on destroying the sun recently. I am not interested in the long term destabilizing or destruction of the Sun per se (though if this is a possible side effect please note this), just the production of flares and CMEs.

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    $\begingroup$ What sort of technology level are we granted? $\endgroup$ – HDE 226868 Jan 29 '18 at 21:57
  • $\begingroup$ Apologies for the poor English. Herniated disc. $\endgroup$ – Englishman Bob Jan 29 '18 at 22:11
  • $\begingroup$ Does it have to be the sun itself (or a similar star) or could it also be a star with substantially different properties? In particular, if you make the stellar wind subsonic, it might open up a bunch of possibilities. $\endgroup$ – leftaroundabout Jan 30 '18 at 1:09
  • $\begingroup$ No. Please stick to the question as asked. Personally I find your proposal fascinating, but I am trying to develop a plot point. However, if I found a post a addressing this topic I would happily upvote it. That is, your offer is interesting, but not germane. $\endgroup$ – Englishman Bob Jan 30 '18 at 14:15
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Let's first think about what causes solar flares. The processes behind them are not substantially well-understood, but we do have some ideas. Magnetic reconnection is one possibility. Essentially, the magnetic field of the Sun quickly changes in shape and topology, releasing a substantial amount of energy. The result? A solar flare, a coronal mass ejection, or something similar. The same sort of process likely happens in flare stars.

So, if you want to trigger a solar flare, what do you have to do? Disrupt the Sun's magnetic field. The great bit about this strategy is that there isn't really long-lasting damage to the Sun, like there might be if you chucked another star at it (pro-tip: don't do this!). If you can, for instance, subject it to another really strong magnetic field, you just might be able to trigger reconnection.

Okay, but how can we do this? The ideal source of the magnetic field is . . .

  • Not very massive, so you don't mess up the orbits of the planets.
  • Stable, so it survives the encounter without triggering some catastrophic magnetic event.
  • Fairly simple, if possible.

1. A magnetar

A close encounter with a magnetar could be a possibility. They're neutron stars with extremely high magnetic fields. Unfortunately, their masses are about two times that of the Sun, but if you're looking for some nice magnetic activity, a pass by a magnetar might be what you're looking for. Plus, you don't need to build anything; these are natural objects.

2. A gas giant

It has been hypothesized that hot Jupiters are responsible for superflares in some Sun-like stars. The theory is that the magnetic field of a gas giant orbiting close to the star becomes entangled with the star's magnetic field. Reconnection eventually happens, giving off a huge amount of energy; superflares can have energy 1,000 to 10,000 times that of a solar flare. Plus, they occur in Sun-like stars, and they can occur many times over large timescales.

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  • $\begingroup$ Hi, I just reread the linked wiki article on hot Jupiters, and noticed the following appended to it: "Not all planetary transits can be detected by Kepler, since the planetary orbit may be out of the line of sight to Earth. However, the hot Jupiters orbit so close to the primary that the chance of a transit is about 10%. If superflares were caused by close planets the 279 flare stars discovered should have about 28 transiting companions; none of them actually showed evidence of transits, effectively excluding this explanation." $\endgroup$ – Random Feb 19 '18 at 18:15
  • $\begingroup$ ^ Does the above mean the hot Jupiter explanation is dead, or am I misinterpreting? $\endgroup$ – Random Feb 19 '18 at 18:16
  • $\begingroup$ Ok, that's very interesting, so forgive me if I misunderstand, but I thought the problem was that we'd failed to detect transit in 279 systems, 28 of which should have been transiting at any given point? Is it really likely that all 28 of them were tilted so that transits were not observable by us? $\endgroup$ – Random Feb 19 '18 at 18:28
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    $\begingroup$ @Era Sorry, I misunderstood your question! My understanding is that the process has been ruled out for quite a number of stars, but that the model itself could still work. In other words, the process should be possible, but isn't used in many of the superflare stars observed. $\endgroup$ – HDE 226868 Feb 19 '18 at 18:34
  • $\begingroup$ Ok, cool. So I just misread the text if that’s the case. Maybe I should run it past space SE. $\endgroup$ – Random Feb 19 '18 at 18:36
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You should look into star lifting

https://en.wikipedia.org/wiki/Star_lifting

The simplest system for star lifting would increase the rate of solar wind outflow by directly heating small regions of the star's atmosphere, using any of a number of different means to deliver energy such as microwave beams, lasers, or particle beams – whatever proved to be most efficient for the engineers of the system. This would produce a large and sustained eruption similar to a solar flare at the target location, feeding the solar wind.

The general idea here is to use orbital power satellites that collect energy from the sun, and then use (in the above case) beams of energy (particle, laser or what have you) to super heat a small section of the sun, causing a sustained solar flare like eruption.

This would seem to fit you needs, perhaps this is on a bit of a grander scale, but I think anything affecting a sun sized body would have a grand scale.

A few natural sources that could cause this effect would be a quasar a pulsar or a GRB (gamma ray burst) whose beam hits the sun, how realistic this is, physics wise, I don't know. But we need a beam of high energy for the above example and well.... it may not be entirely unbelievable. I've seen stranger things in movies, like mini-guns on asteroid mining rigs.

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    $\begingroup$ Both pulsar and quasar emission would be way too faint to do anything here; the flux we observe is simply too small. It's challenging to detect it at all, even with the telescopes and instruments we have today. $\endgroup$ – HDE 226868 Jan 29 '18 at 23:09
  • $\begingroup$ I was assuming it would be an event closer then normal, otherwise we would have probably observed this effect by now. $\endgroup$ – ArtisticPhoenix Jan 30 '18 at 21:45
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You need to decrease the temperature of the corona

A solar flare is caused by magnetic reconnection (probably; I will assume this is true for the rest of this answer). A series of magnetic loops near each other will reconnect with each other in a different topology. Since highly energetic charged particles tend to follow the loops, this reconnection can orphan portions of the magnetic lines of force. These unconnected magnetic helical fields and the charged particles tracing them can then explode outwards in a flare.

Magnetic reconnetion occurs when two (or more) magnetic field lines approach each other. The plasma's electrical resistivity in the boundary region opposes the currents that should be formed by the two fields. This opposition forms a 'potential gap' of sorts, acting in a way like a magnetic capacitor (please don't quote me on that to a physics professor). This is the mechanism that stores up energy. Once the magnetic lines do reconnect, this energy can be dissipated into the 'orphaned' charged particles, giving them their motive force.

Since magnetic reconnection is associated with higher electrical resistivity, in order to induce flares, we want to raise the electrical resistivity. Resistivity is the inverse of conductivity. Figure 2 here shows that electrical conductivity increases with increasing temperature (up to 30,000 K at least...). Therefore, electrical resistivity decreases with _increasing temperature.

Therefore, anyone saying to hit the sun with a lot of energy to cause a solar flare is probably wrong. You want to decrease the energy in the sun's corona along the magnetic field lines. This will lead to more stored energy that can be released by magnetic reconnection.

How to decrease the temperature of the corona? Frankly I have no idea, not even in far out sci-fi terms.

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  • $\begingroup$ Not sure if this would work for such a volatile and stochastic object as the corona, but you can use lasers to cool materials in a process called doppler cooling. $\endgroup$ – forest Jan 30 '18 at 1:04
  • $\begingroup$ A big chunk of carbon would (plausibly) be cooler than the star. Shoot it into the star with your handy dandy mass driver and -- hey presto -- a CME!! $\endgroup$ – RonJohn Jan 30 '18 at 1:51

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