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Old Jul 29th 2018, 06:19 PM   #1
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Plasma?

Recently, when I was in South Carolina, I saw one heck of a thunder and lightning storm. It seemed to have more lightning than rain. I loved it!

Anyway, I saw something that I can't really explain. My parents live in a single level double-wide "trailer." It has floor vents for the heat pump that do not vent or intake from directly outside. We had a lightning strike close by... it hit the yard across the street and basically went right over my parent's house. The odd thing was that there was a glow and even a little discharge of what looked like plasma that came up out of a floor vent. I have never heard of a such a thing. Was it plasma induced by the lightning?

-Dan
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Old Jul 30th 2018, 03:22 AM   #2
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The electrical potential gradients can be huge near a lightning strike.
It would not surprise be if they were locally high enough to ionise the air.

The relative electrical conductivity of the air vent system verses the surrounding structures could have further concentrated these electrical gradients.
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Old Jul 30th 2018, 05:48 AM   #3
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[QUOTE=Woody;41290]The electrical potential gradients can be huge near a lightning strike.
It would not surprise be if they were locally high enough to ionise the air.

QUOTE]


Yes I think that's one part of the puzzle.

Originally Posted by Woody View Post
The relative electrical conductivity of the air vent system verses the surrounding structures could have further concentrated these electrical gradients.

The high conductivity of metal ducts will not concentrate electrical gradients, quite the reverse.



However I would ask squark if the heat pump is air to air?

This will tend to dry the air and allow the potential gradient to be sustained for long enough to cause partial ionisation.
I doubt that the phenomenon was a full plasma.
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Old Jul 30th 2018, 08:33 AM   #4
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Originally Posted by topsquark View Post
Recently, when I was in South Carolina, I saw one heck of a thunder and lightning storm. It seemed to have more lightning than rain. I loved it!

Anyway, I saw something that I can't really explain. My parents live in a single level double-wide "trailer." It has floor vents for the heat pump that do not vent or intake from directly outside. We had a lightning strike close by... it hit the yard across the street and basically went right over my parent's house. The odd thing was that there was a glow and even a little discharge of what looked like plasma that came up out of a floor vent. I have never heard of a such a thing. Was it plasma induced by the lightning?

-Dan
Would conduits to the vent act like a wave guide?
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Old Jul 30th 2018, 10:10 AM   #5
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Originally Posted by topsquark View Post
Was it plasma induced by the lightning?
Yes. Lightning propagates down a column of ionized particles, which is basically plasma.
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Old Jul 30th 2018, 11:03 AM   #6
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Thanks for all the input!

Yes, I believe the heat pump is air to air.

I never actually finished EM II so I only have a vague idea of what happens in wave guides.

-Dan
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Old Jul 30th 2018, 02:57 PM   #7
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Originally Posted by topsquark View Post
Thanks for all the input!

Yes, I believe the heat pump is air to air.

I never actually finished EM II so I only have a vague idea of what happens in wave guides.

-Dan
Some years back when I was working in the desert and living in a portakabin, we found that one could get an appreciable belt by sleeping with the aircon on all night, getting up in the morning and grabbing the door knob.

I am not completely convinced by the waveguide idea. These work for some (usually high) frequency oscillating signal and standing waves.
The lightning is essentially DC and therefore unidirectional and non oscillatory and the pulse is travelling.

The lightning stroke and earth counter stroke will of course be transients with high rise times so the pulse may well be 'guided' in a similar fashion.

Lecherleitung (lecher lines) will show steady discharges in discharge tubes when powered by oscillatory signals.

The phenomenon observed will be a transient ball tracking the lightning stroke.

Lecherleitung will show an array of discharge tubes flicking on and off in sequence as the single pulse travels.

https://www.google.co.uk/search?q=le...w=1366&bih=622

BTW my heat pump is air to water so I suppose I will never experience this phenomenon.
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