What is St. Elmo's fire enrgy source?

[Stanley514]

St. Elmo's fires produce light and therefore useful energy.
https://en.wikipedia.org/wiki/St._Elmo's_fire#Cause
What is the source of this energy? I mean from which to which form does it convert to?

 

[Simon Bridge]

It's electrostatic ... ultimately from the Sun.
http://science.howstuffworks.com/nature/climate-weather/atmospheric/st-elmo-fire1.htm

The passage in wikipedia you quoted actually tells you where the energy comes from...

 

[Stanley514]

It's electrostatic ... ultimately from the Sun.
http://science.howstuffworks.com/nature/climate-weather/atmospheric/st-elmo-fire1.htm

The passage in wikipedia you quoted actually tells you where the energy comes from...

I thought that in order to obtain useful energy, a current should flow. Yet, according to their description all this phenomenon happens before conditions for lightning are completely created. In my opinion a simple static field cannot generate an energy to do a work...

 

[russ_watters]

I thought that in order to obtain useful energy, a current should flow. Yet, according to their description all this phenomenon happens before conditions for lightning are completely created. In my opinion a simple static field cannot generate an energy to do a work...

Where are you getting the idea that this can generate "useful" energy/work? Or that it happens before there is a significant charge separation?

 

[Nugatory]

I thought that in order to obtain useful energy, a current should flow

That's not right - you can get light without any current flowing if you can just move enough charged particles around enough. The electrical field is quite strong enough to separate electrons from their parent atoms leaving us with a mixture of negative-charged electrons and positive-charged ionized atoms. Thermal motion in tis sea of charged particles then generates light.

 

[Simon Bridge]

I thought that in order to obtain useful energy, a current should

flow.

Basically? Your thought on this matter is mistaken.

In my opinion a simple static field cannot generate an energy to do a work...

Unfortunately Nature does not care about opinions, yours or mine.

Have you never seen a demonstration where a florescent light glows in an electric field, with no current passing through it?
http://techtv.mit.edu/collections/p...uorescent-and-neon-tubes-in-an-electric-field

 

[Stanley514]

Where are you getting the idea that this can generate "useful" energy/work? Or that it happens before there is a significant charge separation?

Well, if there is a lights, we could convert this light into electricity with help of photocell and make it some useful work to do.

 

[Stanley514]

Have you never seen a demonstration where a florescent light glows in an electric field, with no current passing through it?
http://techtv.mit.edu/collections/physicsdemos/videos/5766-fluorescent-and-neon-tubes-in-an-electric-field[/QUOTE [URL='http://techtv.mit.edu/collections/physicsdemos/videos/5766-fluorescent-and-neon-tubes-in-an-electric-field[/QUOTE'][/QUOTE][/URL]
[URL='http://techtv.mit.edu/collections/physicsdemos/videos/5766-fluorescent-and-neon-tubes-in-an-electric-field'][/PLAIN]

[URL='http://techtv.mit.edu/collections/physicsdemos/videos/5766-fluorescent-and-neon-tubes-in-an-electric-field'][/PLAIN]

[URL='http://techtv.mit.edu/collections/physicsdemos/videos/5766-fluorescent-and-neon-tubes-in-an-electric-field']But in this case we are dealing with a changing, not with completely static electric field, don't we? There should be some change in a field's intensity to do some work.[/URL]

 

[russ_watters]

Well, if there is a lights, we could convert this light into electricity with help of photocell and make it some useful work to do.

Sure, but very, very little. I'm not sure it could generate enough to call it "useful". Still, again, this doesn't imply a conservation of energy issue. I'm not seeing a problem here.

 

[Stanley514]

Sure, but very, very little. I'm not sure it could generate enough to call it "useful". Still, again, this doesn't imply a conservation of energy issue. I'm not seeing a problem here.

Even amount of energy sufficient to power a pocket calculator is useful. I wanted to know when it came from. Is there a changes in electric field?

 

[russ_watters]

Your article alludes to the source being the thunderstorm, but more specifically it is friction stripping and moving electrons around. Similar to when you shuffle your feet on a carpet:

http://scijinks.jpl.nasa.gov/lightning/