Power surge video - why does the spark travel?

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Discussion Overview

The discussion revolves around the physics of a power surge video, specifically addressing why the spark appears to travel down the power line. Participants explore various hypotheses related to the mechanisms at play, including the effects of wind, ionized air, and electromagnetic forces.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants suggest that the Lorentz force may be responsible for pushing clouds of ionized air away from the power source, although there is uncertainty about the direction of this force.
  • One participant compares the phenomenon to a rail gun, mentioning Lenz's law and the idea that the current loop area increases to reduce changes in magnetic flux.
  • Another viewpoint questions whether the observed effect is due to a spark or combustion, noting the presence of a smoke trail behind the flame.
  • Some participants propose that wind is a significant factor, with one participant recalling experiences from rocket-triggered lightning experiments and suggesting that the movement of the arc is due to a trail of ionized air being blown by the wind.
  • There is a challenge to the wind hypothesis, with participants noting that the trees in the video show no signs of wind effects, questioning the visibility of such wind on bare trees.
  • One participant mentions the speed of the arc, estimating it at about 10 m/s (20 knots), and argues that this speed would not produce dramatic effects on the trees if wind were the cause.
  • A comparison is made to a Jacob's Ladder, suggesting a similar principle may be at work in the observed phenomenon.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the cause of the spark's movement, with no consensus reached on whether wind, electromagnetic forces, or other factors are primarily responsible.

Contextual Notes

Participants note various assumptions and conditions, such as the direction of the Lorentz force, the visibility of wind effects on trees, and the nature of the spark versus combustion, which remain unresolved.

Who May Find This Useful

This discussion may be of interest to those exploring the physics of electrical phenomena, atmospheric effects on electrical discharges, and the interplay of forces in such events.

Borek
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Any idea what is the physics behind? Why does the spark travel down the line?

 
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Maybe the Lorentz force pushing clouds of short-circuiting ionized air away from the power source? (I'm not sure I have the direction correct, but I think it would be away...?)
 
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berkeman said:
Maybe the Lorentz force pushing clouds of short-circuiting ionized air away from the power source? (I'm not sure I have the direction correct, but I think it would be away...?)
That's my guess. Like a rail gun! The direction is always to make the current loop area increase, to reduce the change in magnetic flux enclosed as the current increases. Lenz's law, I believe.
 
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Is it a spark or combustion. I see what appears to be a smoke trail behind the flame.
Somewhat like line of gunpowder in the old westerns.
 
The title of the video said storm, so my guess is just plain old wind.
1642024295727.png


My firm used to do rocket triggered lightning experiments as shown in the picture. The parallel paths in the picture are repeated strokes. The total time duration is probably 0.3 seconds. The mechanism of horizontal movement is simply a trail of ionized air being blown by the wind.

In the case of the video below, we have continuous arc rather than separate strokes, but still there is a patch of ionized air being blown by the wind. Some of the ions get left behind, but new ones are created each instant.

In this video at 2:53-3:04 ask yourself why this arc wants to move to the left and why a long U rather than a shorter one. IMO, it is once again simply wind.

p.s. I miss Jim Hardy too. He was the best.
 
Last edited:
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oh that's a good video! Listen to Mom, at 3:15 saying "get in here!"
 
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gmax137 said:
oh that's a good video! Listen to Mom, at 3:15 saying "get in here!"
"Hey Darryl, grab your little brother Darryl and get your butts back inside!"
 
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berkeman said:
Maybe the Lorentz force pushing clouds of short-circuiting ionized air away from the power source? (I'm not sure I have the direction correct, but I think it would be away...?)
I was thinking IxB.

I was also wondering if it phase-to-phase and/or phase-to-neutral/ground.
 
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anorlunda said:
The title of the video said storm, so my guess is just plain old wind.
Aint no wind in those trees in the video... :wink:
 
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gmax137 said:
oh that's a good video! Listen to Mom, at 3:15 saying "get in here!"
Good thing she didn't tell him to 'go fly a kite, and here's a key'.
 
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anorlunda said:
trail of ionized air being blown by the wind.
Similar principle to a Jacob's Ladder?
 
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berkeman said:
Aint no wind in those trees in the video... :wink:
I'm not convinced. The arc in the video moved at about 10 m/s (20 knots). The trees had no leaves. 20 knots of wind does not make dramatic visible effects on bare trees. Wind is still my wager.
 
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anorlunda said:
I'm not convinced. The arc in the video moved at about 10 m/s (20 knots). The trees had no leaves. 20 knots of wind does not make dramatic visible effects on bare trees. Wind is still my wager.
+1
https://www.kxan.com/news/stunning-...surge-traveling-down-power-line-during-storm/
The winter storm moving through the area is the same as the one knocking out power to cities in Texas and dropping snow from the Gulf of Mexico to the Ohio River Valley.

Easy to see the arc being affected by wind here causing wire slapping.

 
  • #15
Fascinating video, @Borek!
It's eerily beautiful with the different colors of the arc/spark.
 

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