Lightning

[meemoe_uk]

Has anyone here smelt the sulfur smell after a powerful thunderstorm?

I just had that discovery moment when I connected the sulfur in old stories of thunder storms ( fire and brimstone ), the prevalence of sulfur on the active moon Io, and the abundance of sulfur around Earth's volcanoes.

Seems possible that the Earth has its own plasma cells, like those on the sun, and the Earth's crust sits on top of these plasma cells, resulting in plate tectonics. Are these plasma cells fusing oxygen to create sulfur and heat like on Io?

What is powering these plasma cells with enough energy that they can fuse oxygen?

Also this subsurface fusion can alternative-explain the power output of other planets, such as Jupiter. At just 150km below its surface, Jupiter's temperature is about 150C.

[tayga]

Are you sure that's sulfur you're smelling and not ozone?

Ozone was proposed as a new substance in air in 1840, and named, even before its chemical nature was known, after the Greek verb ozein (ὄζειν, "to smell"), from the peculiar odor after lightning storms.

http://en.wikipedia.org/wiki/Ozone




(Hey, look at us Brits spelling sulfur properly )

[meemoe_uk]

i haven't smelt sulphur after a thunderstorm. I've heard stronger thunderstorms, typical of warmer climates, produce a sulphur smell.

[starbiter]

Dr Velikovsky wrote about sulfur in the V archive.

http://www.varchive.org/itb/sulphur.htm

[tayga]

I was about to suggest that the smell of ozone might be confused for sulfur until I read the Velikovsky link. So I looked to find any other mention of oxygen being transmuted to sulfur. I can't corroborate it.

[starbiter]

This video seems interesting.

http://www.youtube.com/watch?v=MymFcb9U1Ck

[celeste]

kiwi, Thanks again. It is correct that sound (at least in the case of thunder),is not from vibration of air molecules. We know it's an electrical event,and that the pressure wave is radially (not spherically)propagating. Here is what I think happens:
When we have a lightning flash, the charge spirals tightly along the current. We've seen how the radial force of that spiraling charge can crush a lightning rod. But what happens after recombination of ions to neutral air molecules? Ions spiraling rapidly around the current, become neutral atoms thrown off with equal speed radially from the current. It is not vibration that causes thunder, but the outward blast of air molecules. Does that sound right?

[justcurious]

I suppose when we say thunder, we are referring to the sound?

Check out this home video of a crude plasma speaker.
This is not your normal speaker.
The sound is created by arc'ing, just two wires in the air!

http://www.youtube.com/watch?v=rasp88nbsRw

Youtube is full of variants of home made plasma speakers.
Nice to have an easily reproduceable phenomenon that anyone can study, perhaps this can shed some light on how lightning produces sound?

[justcurious]

Sound is matter moving in a wave, air being dispaced.
When electric currents run through plasma air, they induce a circular magnetic field around them which contracts the plasma carrying the current (z pinch) and hence we have an arc or filament instead of a blob. The magnetic field would be proportional to the change in electric current and the z-pinch would vary proportionaly to this magnetic field strength. The varying strength of the z-pinch would displace the air around it and create sound waves.
Based on the high fidelity of the sound coming from some of these crude plasma speakers, I would tend to think the audio is created by z pinch effect rather than some thermal process.
Same with thunder... we know there will be an enormous pinching of the air as the current surges followed by a swift releasing of the compressed air and hence the sound like an explosion. Plasma 101 explains this very simply.
Or maybe I missed something, what do I know...

Edit: aha, the article mentionned in the first post has these final words in its abstract...

The pinch force was found to be far too small and in the wrong direction to be the cause of thunder. Longitudinal and alpha-torque forces act in the correct direction but, so far, quantitative agreement has not been achieved. This may have to wait for a complete Ampere MHD.

I don't have access to the full article. The z pinch would have been in the wrong direction??? Am I totaly wrong or what?

[celeste]

justcurious, I believe they are saying the pinch force is radially inward,not outward. But there is more than just compression and then relaxation after z-pinch. http://apod.nasa.gov/apod/ap100112.html I'm not sure if this is like the catastrophic "whiplash" like destruction discussed in the water bridge.
That is, we know there is a z-pinch in lightning,but is it the functioning,or the catastrophic failure of z-pinch that causes the thunder?

[justcurious]

justcurious, I believe they are saying the pinch force is radially inward,not outward.

I don't know what they are saying, don't have access to the full article., although it does seem a bit old (1989).
It doesn't matter if the Z force is outward or inward. If the force is radially inward, the "change" in the applied force will compress/uncompress the plasma (free-to-move charges) and create sound waves. Not saying that there may not be other forces at work that can also contribute to the sound effect in thunder. But for the impressive home-made plasma speakers, I can't think of a better explanation (varying electric current -> varying z-pinch force -> varying sound waves).

How else would you explain music being played with two wires and the speaker being nothing but air in between the wires.

[justcurious]

justcurious, I believe they are saying the pinch force is radially inward,not outward.

I don't know what they are saying, don't have access to the full article., although it does seem a bit old (1989).
It doesn't matter if the Z force is outward or inward. If the force is radially inward, the "change" in the applied force will compress/uncompress the plasma (free-to-move charges) and create sound waves. Not saying that there may not be other forces at work that can also contribute to the sound effect in thunder. But for the impressive home-made plasma speakers, I can't think of a better explanation (varying electric current -> varying z-pinch force -> varying sound waves).

How else would you explain music being played with two wires, whereby the speaker in this system is nothing but air in between the wires.

[StandingWave]

Could the mystery booms being experienced in various places around the world recently be caused by the same dynamic as thunder but without the flash of lightning?

[garitd]

I am very eager to see this thread continue. And I hope to eventually see some kind of diagram. That would help me immensely to understand.

[justcurious]

I am very eager to see this thread continue. And I hope to eventually see some kind of diagram. That would help me immensely to understand.

Well, I don't claim with any certainty that the z-pinch is wholly responsible for the sound waves, but I can't think of anything else. The z-pinch seems like an obvious hypothesis.

Diagrams.... first let's look at the effect, see the below pictures (taken from the Essential Guide chapter 6):


Left: The field generated by a fast 2 kj discharge through 3-turn heavy wire crushed this can. Right: Nature's lightning z-pinch deformed this metal rod. Images credit: Wiki Creative Commons

As you can see above, lightning is powerfull enough to compress and squeeze radialy inward a metal rod.
So imagine with ionized air where the particles are free to move (air molecules, ions and electrons).

The physics and math behind it is classic EE textbook stuff. I find that the Esential Guide explains it pretty well but here is a simple diagram demonstrating the principle:



In the above diagram we can see that the wires attract each-other. The magnetic field generated by one wire pulls on the other parallel wire. From what I understand, in plasma, the current is not bound by a physical wire, and hence the currents' tendency to bunch up together (many small wires into a larger wire so-to-speak), and this would be called the z-pinch. Note that the equations seen in the above diagram are simplified equations based on infinitely long wires, perfectly parallel etc (ie academic). You need to familiarize yourself with the 4-5 essential mathematical equations grouped under the umbrella of "Maxwel's Equations". The Essential Guide has an appendix which goes over some of the math. Since the z-pinch varies with varying current, I would expect this to generate sound waves (ie air being compressed and decompressed in direct proportion to the current variations (ie discharge).