If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #118
Joined: Fri Feb 10 2006, 05:35AM
Location: Woodridge, Illinois, USA
Posts: 72
Amazing video and image of a powerful lightning strike vaporizing a wire that was strung between two buildings in Russia. Captured from two different perspectives, the steel support wire is explosively vaporized in a shower of sparks. Also evident is more aggressive vaporization along the shorter path:
Exploding wires are loud.... lightning-exploded wires are VERY LOUD!
Registered Member #118
Joined: Fri Feb 10 2006, 05:35AM
Location: Woodridge, Illinois, USA
Posts: 72
radiotech wrote ...
Why was the wire strung between those two buildings and what evidence is there that it vaporized?
As I understand it, a fiber optic link had been strung between the tops of the two buildings. This is apparently a rather common practice in that part of the world. The link was mechanically supported by a steel cable, and it was the latter that conducted the discharge current, exploding in a shower of burning-steel. The non-conductive fiber link can be seen as a faint dark line spanning the gap in the still images (before it fell). From the volume of sparks produced (those are 18 story buildings!) it must have been a pretty stout cable. Interestingly, the ultrabright flash that accompanies true wire explosions (channel reignition and follow-through current through the air-metal plasma) was not present. So, this may not have been a true "exploding wire" event - just a very energetic disassembly of the cable...
Registered Member #834
Joined: Tue Jun 12 2007, 10:57PM
Location: Brazil
Posts: 644
It's interesting to see the greater power dissipation at the shorter side of the cable. A nice demonstration of how power distributes between two parallel resistances.
Registered Member #118
Joined: Fri Feb 10 2006, 05:35AM
Location: Woodridge, Illinois, USA
Posts: 72
Microwatt wrote ...
how much energy do you think was expended in the cable?
Interesting question! I created a small spreadsheet to ballpark some numbers. I assumed that the support cable was made from 3/16" diameter stainless steel 302 cable. based on the building total height of about 20 stories (to top) and 10 feet/story), I estimated that the distance between buildings was about 400 feet. It looks like the stroke connected at a point 170 feet (short length) and 230 feet (long segment). Assume both ends of cable are solidly grounded. The electrical resistivity for SS 304 electrical is 72 microohm-cm, so the estimated resistance of the short segment is ~0.79 ohms, and the long segment is ~1.05 ohms. I guesstimated peak current and duration for "typical" positive and negative polarities using data from Bazelyan and Raizer's "Lightning Physics and Lightning Protection". For a negative CG strike, I assumed that the first return stroke peak current was 50,000 A, and its duration was 100 microseconds. For positive CG lightning, I assumed a peak current of 200,000 A and duration of 500 microseconds. Following is the estimated Joules/segment (simplistically asuming that cable resistance stayed constant vs temperature), and the estimated temperature rise for each cable segment for negative and positive CG strokes:
If "typical" Negative CG strike: Wshort = 50 kJ in shorter segment Est Temp Rise: 17.3 C Wlong = 40 kJ in longer segment Est Temp Rise: 9.7 C
If "typical" Positive CG strike: Wshort = 5.16 MJ in shorter segment Est Temp Rise: 2415 C Wlong = 3.87 MJ in longer segment Est Temp Rise: 776C
YMMV, but based upon the above results, it looks like the higher peak current and longer duration of a positive CG lightning strike is necessary to account for the observed results...
Registered Member #480
Joined: Thu Jul 06 2006, 07:08PM
Location: North America
Posts: 644
Bert -
Aside from the lightning discharge and the vaporized conductor, there is an interesting image artifact very visible in your 3rd link (the enlarged still image).
All the illuminated windows in the high-rise buildings have a "smear" of light trending slightly up and to the right. However, not all the light sources visible in the image have this smear; some (like individual lamps in the foreground, at the bottom of the image) are crisp, with no "coma".
So the "smaers" of light don't appear to be the result of camera movement; what are we seeing?
Registered Member #118
Joined: Fri Feb 10 2006, 05:35AM
Location: Woodridge, Illinois, USA
Posts: 72
Herr Zapp wrote ...
Bert -
Aside from the lightning discharge and the vaporized conductor, there is an interesting image artifact very visible in your 3rd link (the enlarged still image).
All the illuminated windows in the high-rise buildings have a "smear" of light trending slightly up and to the right. However, not all the light sources visible in the image have this smear; some (like individual lamps in the foreground, at the bottom of the image) are crisp, with no "coma".
So the "smaers" of light don't appear to be the result of camera movement; what are we seeing?
Herr Zapp
Interesting observations! However, I suspect the smears are indeed due to slight camera movement. The still camera appears to have been physically closer than the video camera. Perhaps the still camera was slightly shifted by acoustic blast(s). Some of the unsmeared light sources in the foreground appear to be reflections of the lightning flash, so smearing of these would not be expected. Others foreground lights, such as the automobile taillights, appear to be comprised of multiple (3-4) discrete spots that trace a similar trajectory as the smeared sources. I'd surmise that these are from the strobing effect of the pulsed taillight drivers used in modern cars. However, I can't explain why a single set of auto headlights (also in the foreground) does not appear to be smeared. Perhaps the car's movement partially compensated for the camera movement?
BTW, after reviewing the video clip again, multiple strikes are evident... so the bolt was NOT a single massive positive stroke. Statistically, a small percentage (1% or so) of negative CG bolts exceed 200 kA+ during the first return stroke, and 100+ kA on subsequent strokes. In between strokes, hundreds of amps of "tail" current may flow. Negative lightning has a higher di/dt so skin effect and current diffusion effects (not taken into account in my earlier simplistic analysis) may play a more profound role than bulk resistivity, especially for slightly ferromagnetic alloys such as SS 302/304. Flash surface heating/ablation of the cable's outermost layer may be the result.
This is one fascinating event, and is especially amazing since it was simultaneously captured in separate video and still shots! Some awesome pulsed power effects are at work here...
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
Natural Exploding Wire - a massive Russian lightning bolt vaporizes wire connecting two buildings
