Researchers explore how storms on Earth create extreme bursts of radiation | Hacker News Reader

Researchers explore how storms on Earth create extreme bursts of radiation

nature.com

74 pointspseudolus22 comments

I read this mainly to see what Dr. Dwyer was up to in regards to this. I was in the same grad school as his group at FIT. I was also working on gamma ray detectors at the time, so we would occasionally talk. Their big challenge was the range of the rays in the atmosphere. But I also think that they had a lot of fun - they would initiate lightning strikes by shooting rockets into clouds. That way they knew where to set up their detectors.

http://www.lightning.ece.ufl.edu/PDF/Dwyer_et_2009a.pdf

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

https://www.youtube.com/watch?v=buSaGIoNXu8

Reading the wiki and some related patents I am curious how many such rockets would be required to sufficiently protect a region from random lightning strikes.

Are there methods to determine the potential for a storm to generate lighting or simply how much energy is potentially there to create them?

Its not my field, but I'm pretty sure that the potential for a storm to generate lightning is strongly related to the CAPE (convective available potential energy), which is often measured by meteorologists using sounding balloons, or I presume, using more modern indirect (radar,lidar) methods.

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

I live in Florida, where we have a fairly high frequency of lightning strikes (although nothing like Congo). Here is a map of global lightning strikes per year per km^2.

https://en.wikipedia.org/wiki/Distribution_of_lightning#/med...

Whether a single rocket system would drain enough charge from a storm to prevent other lightning strikes, I don't know.

I used to think about how to set up a continuous conduction path to the ionosphere as a form of power generation. Any material path would likely be destroyed, but in theory a stabilized plasma could provide essentially an unending lightning strike draining the global atmospheric charge imbalance. But, this isn't an easy problem (it's a long way up to the ionosphere), and the amount of energy in global lightning is surprisingly small when compared to other natural sources like solar, tides, geothermal, etc. Very concentrated though!

> initiate lightning strikes by shooting rockets into clouds

That's what should be shared when people think that science isn't heavy-metal enough.

>Crucial to their plans was making cheap, tabletop γ-ray detectors that they could install in dozens of sites.

On a related note: there's a citizen science experiment that uses a volunteer-run array of old smartphones with taped over cameras to detect particle showers caused by ultra-high energy cosmic rays.

https://en.wikipedia.org/wiki/Cosmic-Ray_Extremely_Distribut...

https://arxiv.org/abs/2010.08351

https://arxiv.org/abs/1410.2895

If I have to be careful with 20kv discharges generating x-rays, certainly it's within the realm of possibility that lighting bolts are generating y-rays, no?

They want to figure out the details of why and how it happens.

I think snarfy is expressing incredulity that meteorology doesn't already account for these types of emmissions. Analogously, suppose the headline had read

> Water flows downhill. Scientists want to know why.

"But gravity makes everything flow downhill, right? What makes water especially worthy of investigation." Surely this is a reasonable reaction.

We don't entirely have a mechanistic explanation for gravity either.

Yeah, I'm not a physicist sort, so I wouldn't know, but I was under the impression that while we have a good model for the "what" of gravity in most "classical" scenarios, and we can even model some weird gravity effects in weird situations, not all of the "whys" are answered and people don't know how to model gravity together with other phenomena.

I agree it is. And C.T.R. Wilson was talking about it in 1925. But the TGFs mentioned in the article are incredibly bright, and what we're trying to understand (I work in this field) is why one lightning flash makes only a modest amount of x- and gamma-rays, kind of what you might naively expect, and another makes a mind-boggling million times as many, which is not as simply understood.

Cool to see this on HN! I worked for Prof. Smith (quoted in the article) as an undergrad. TGFs also emit beams of electrons. One of my projects was investigating whether we can detect these beams of electrons bouncing back and forth along Earth's magnetic field lines.

Hi, Paul! :) I was sent here by Greg Bowers. -David

I heard that lightning is triggered by cosmic ray particles. A seed in a supersaturated solution situation.

And cosmic rays always come from very very far away.

So a lightning bolt is literally an amplified message from beyond.

I don’t think that’s always the case as it doesn’t really account for ground-to-cloud lightning strikes

Well I dunno about "always the case", but it's certainly accountable for ground-to-cloud.

What the seed does is create a place of high potential. I think which way the lightning flows is arbitrary at that point.

The case in the paper I linked above was an intracloud flash, but nearly all cloud-to-ground flashes also start with a breakdown up in the cloud, so I agree that any model of lightning initiation can apply to both intracloud and cloud-to-ground flashes.

Navajo mythology says that a man who was struck by lightning cannot be trusted. Not because he's evil or damaged, but because he has been touched by profound alienness. He's too weird to predict.

People in the field have gone back and forth on this, but you might like this paper, which is the best piece of evidence I've seen for it in a specific case of a specific flash. Look in particular at Figure 6 to see the lightning breakdown starting just at the ionization front (curved surface) of the cosmic ray shower: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/201...

Thundercloud Project: Exploring high-energy phenomena in thundercloud and lightning (2020) https://academic.oup.com/ptep/article/2020/10/103H01/5885093 HTML

Always thought it was a case of Bremsstrahlung: https://en.wikipedia.org/wiki/Bremsstrahlung

https://archive.is/zpyoo

You can find PDFs of that article if you search. It's fascinating.

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