March 2, 2014 dendritic form

[kell1990]

http://www.thunderbolts.info/wp/2014/03 ... -sculptor/

This is a spectacular image, Mr. Smith, this lightning flash between mesas.

I can't help but notice that this seems more like a tree than a lightning bolt. Did this bolt emanante from the ground, like a tree, or did it collect from the sky to land on a specific point? Is there some way to determine the direction of flow of lightning bolts?

[Infinion]

I can't help but notice that this seems more like a tree than a lightning bolt. Did this bolt emanante from the ground, like a tree, or did it collect from the sky to land on a specific point?

This looks like positive streamers eminating from the ground and growing upwards. The positive leaders will branch out into a tree-like shape as they leave an ionized channel behind them. One of the leaders will reach a cloud of negative charge first and the full discharge will follow that leader's channel.

I've never seen a discharge where multiple leaders combine to form a single filament to the surface. Both positive and negative leaders grow in any direction where they see the highest electric field strength. The strength of electric field between two oppositely charged regions in the air is typically non-uniform, so leaders will spread out and follow the immediately highest field strength closest to them.

here's a cool java app where you can simulate lightning, or more specifically, negative leaders that form the tree like patterns you see to get to a positive surface.

http://gamma.cs.unc.edu/LIGHTNING/applet/docs.html

if your java freaks out about security and blocks the app, click start on your pc and search for "configure java" -> go to security -> under exception site list click "edit site list" -> copy the address the app is on and add the site.

you should be able to view the app after that.

Is there some way to determine the direction of flow of lightning bolts?

AFAIK from looking at images of lightning in nature and the streamers from my high voltage experiments, filaments always begin from a single point on a surface with the highest potential, then grow and twist into tree-like streamers where there lies some lower potential or oppositely charged region in the distance. So as far as figuring out what direction they go, it's from point to branch.

The actual flow of charge is in both directions. The only reason current in conductors flows in one direction is because ions are bound in the lattice that make up the conductor while valence electrons can be freely pushed around by electric fields (voltage). Even then, there are still electrons that are unable to move since they are not in a valence shell, so they are just as bound as the ions are.
With plasma that's all different. There is no lattice to constrain anything, so there can be a positive ion flow and an electron/negative ion flow. It is for this reason that current in lightning does not flow in one direction, but both.

[starbiter]

http://www.thunderbolts.info/wp/2014/03 ... -sculptor/

This is a spectacular image, Mr. Smith, this lightning flash between mesas.

I can't help but notice that this seems more like a tree than a lightning bolt. Did this bolt emanante from the ground, like a tree, or did it collect from the sky to land on a specific point? Is there some way to determine the direction of flow of lightning bolts?

The quote below from the TPOD states it's an artists impression.

"In the image at the top of the page, the artist’s impression of past electrical events indicates that lightning erosion could have been far more devastating in the past, creating the fundamental shapes that are observed today. That basic order is now being sculpted by the same power as that in the past, but on a much smaller scale."

It's still cool.

[henrybroadbent]

Hi Stephen,
My dictionary says the peculiar tubes formed in sand are spelt fulgurites. I have a little one picked up near a local beach about 1.5inch in diameter with two channels about 1/2inch in diameter which twist around each other. It is only 6inches long and less than half a turn in that length. Mungo Jupp also adds to the twists of lightning with the suggestion that it can cause instant fossils as he reports occurred where a sustained power line fault persisted for some time through tree stumps.

Henry Broadbent

[Steve Smith]

Kelli1990, I created the composite image of the lightning and Monument Valley using a graphical editing tool. It was many years ago, so I don't remember what the program was. The "lightning" is a discharge from a Tesla coil through water to another terminal.

Henrybroadbent, that's interesting about your fulgurite. Usually, the holes in the beach are so small that they're missed. Since lightning is a collection of hollow tubes that rotate around each other, your "twisted pair" seems logical.

Infinion, yes, there are negative and positive lightning bolts. The vast majority of lightning bolts send negative streamers toward the ground (in cloud to ground lightning), while positive streamers are induced to flow upward from objects below: blades of grass, fence posts, etc. Once the negative streamer contacts the positive leader, the flash travels up to the clouds.