Pinpointing solar storms

Finding the source of high energy particles in the Sun
09 March 2021

Interview with 

Stephanie Yardley, University College London


The sun


The Sun occasionally has storms of its own, geomagnetic storms, and when they happen, the Sun shoots high energy particles out, and some of those can head towards the Earth. When those particles hit the planet they can interact with Earth’s magnetic field and have all kinds of effects. If it’s mild, it can create things like the Northern Lights, but strong ones can disrupt electricity grids, satellites, and even cause blackouts. But they’re very hard to predict. Stephanie Yardley from University College London works on these phenomena, and was worked to pinpoint them, when might make it easier to get a little warning. Adam Murphy, as well as guests space scientist John Zarnecki and pharmacist Bahijja Raimi-Abraham, asked her how these events happen...

Stephanie - We have disruptions that occur both in space and in the atmosphere. A couple of the main things that we're concerned about are firstly, crewed space flight. There's a huge radiation risk associated with these events. And so this is important for astronauts, for example, or also airlines with passengers and crew. But also they can damage our electronics; particularly our satellites as well. So this is why we want to be able to predict these events, so that we can mitigate some of the risks associated with them.

Adam - And then can you tell us about the work you've done helping to pin them down?

Stephanie - Basically, for the first time we found the specific source regions of these energetic particles. And to do this, we've used a specific chemical fingerprint, and we've used multiple space-based observations; we have a satellite that sits in space that is measuring the particles that hit it there, and then we have another satellite that's looking at the sun's upper atmosphere. And we've basically found the same fingerprint in both these observations, and so we've essentially traced these particles back to the source region on the sun. And we found that these particles are actually confined low down in the sun's atmosphere, and are constrained by very strong magnetic fields.

Adam - How does knowing where they are in the sun give us any indication on how to predict them?

Stephanie - We already put out alerts; we have space weather prediction centres in the US and the UK that put out alerts for these strong radiation storms. However, we often get false alerts, and these events don't arrive at earth or they're just not effective at earth. And so really we need to understand more about the properties of the source regions to be able to understand whether these are going to be effective. So what we can actually do is look at a source region then on the sun and say, "well we think this is going to essentially produce one of these particle events," and this will give us more warning. Currently a lot of the prediction that we do is in progress, so when an event has already occurred and the particles are arriving, then we can say, "okay, we can model this event, and this is what the fluxes arriving at earth are going to look like." Which obviously is a bit late in the day to do so! So by understanding these source regions, not only can we look out for these source regions that are going to produce these events, we can also improve some of the models that we use to model these events.

Adam - How big a threat is this actually? Because it still sounds quite abstract in some regards. So what could it actually do?

Stephanie - These events are quite frequent. There's about a hundred events that occur every solar cycle. Now the solar cycle happens is on the order of 11 years, so we get a hundred events every 11 years. Not all events cause us issues here on earth; and actually it's some of the more extreme events - so maybe we get a couple every 11 years - that might cause an upset in some sense, or would increase the radiation risk to airline passengers and crew. So maybe once a decade or so, you might expect to receive over your yearly dose of radiation. And then we get these even more extreme events that occur every 100 years or every 150 years, which would be absolutely disastrous; we'd have to ground flights, essentially.

Adam - And just to come to you, John - what are your thoughts on this kind of thing?

John - I was thinking while you were talking that if you really get to the point where you can predict these things reliably - and reliability I guess is the key here - you actually stand to make a lot of money, don't you? Because there are presumably people around such as, I don't know, power companies and people who look after communication systems, who would actually pay you a bit of money if you could give them reliable forecasts.

Stephanie - Yeah, I completely agree. Maybe in the future then, space weather consultancy would be a thing. And this is something that they're already interested in - you have, say, the national grid are already interested in these things. We have a lot of what we call 'end users' that are interested in using these forecasts. And even the airlines are starting to be more interested in this, and the government have actually recently put 20 million pounds into funding a huge project, which is how I'm employed, and this is what I work on now! So yeah, we're really interested in this, and hopefully over the next couple of years we will be able to see some results.

John - And presumably if we ever get to fly again, we should check in with you before we go, to check if the sun is behaving on that day...

Stephanie - Yeah. This is the problem: the sun doesn't necessarily behave, and it doesn't behave how we expect it to behave. These events can be quite random. This just obviously adds to the problem of these events. But it's certainly something that we need to be considering, particularly for, obviously, crewed space flight, astronauts going to Mars; but also for passengers and crew on airlines. And it's something that we don't think enough about.

Adam - Bahijja, when we were talking about Perseverance, you were quite excited about space in that regard. How do you feel about these kinds of things?

Bahijja - So many years ago, I was a postdoc at UCL and I started a social enterprise called STEAM:ED Collective, where the aim was to engage the public with STEM research through street art. And I had the amazing chance to meet somebody called Steve Fossey who's at UCL, and at the time, there was a big thing of him discovering a supernova - I think it's 'SN 2014J' - and we worked together to collaborate, and that's when I learned about supernovas. And when we went to the observatory in Mill Hill and we got to look at the sun, which... blew my mind. You can tell I'm so excited! So I find it very interesting. We curated a street art mural in Brockley - part of Brockley Street Art Festival, it's still there - and one of the things in our discussion... we were talking about sometimes the separation between what's going on in space, out there, versus how it relates to us on earth. And so that's when I learned about the supernovas emitting different elements, and also even just how the su engages with the supernova and how the elements, one of the main elements that that supernova released, was iron, and that's why we have iron in our blood. We wanted to say supernova in our blood, but that didn't go down well, so we had to write supernova in our hearts. So this is just really fascinating. And I would love to know more about the connection between the space weather and Earth weather, and is it specific... because you would assume it would affect the whole planet in one go. Is that the case, or does it just affect different areas of the planet that are more susceptible to different things?

Stephanie - Yeah, so it's really interesting what you've just said, particularly the project. I like to also engage in... we do some space art, so I like to engage in those kinds of projects, and they're really interesting and fascinating. And again, it ties in very nicely what you said about the supernova. What we actually used is these chemical fingerprints; so we were looking at the ratio of silicon to sulphur, and this is how we located the particles; so similar to you talking about the iron in the supernova. This is another problem with these events: they don't affect the Earth as a whole, necessarily. You might have locations where you see stronger effects, so you might see stronger effects in the UK, or at the poles, or in America. And so a lot of effort goes into modelling these particles and how they interact with the Earth's atmosphere, and also the eruptions as well, how they interact and what damage they cause. So it's really tricky. It's a really tricky problem with many, many avenues that you have to look at; so you don't have to just think about the sun, you have to think about propagation through space, and then you have to think about Earth. And then you get these really interesting studies where actually... so for example, at one of our particular events, they registered these particles at Mars with the Curiosity rover. So you can get these particles, energetic particles, and these eruptions making it all the way through the solar system.

John - We aurorae, don't we, at Saturn and Jupiter. So that's a great indication of the influence of the sun; it stretches, as you say, right across the solar system.

Stephanie - Exactly. And some of their aurorae is even more complicated than it is on Earth, because you've got all the different moons that are involved, and they're even more energetic as well because the magnetic fields are stronger. So that's a whole different avenue that a lot of scientists work on as well: modelling the aurora on Jupiter and Saturn.


Add a comment