What caused this mysterious A-Bomb sprite over the Caribbean?

[davenn]

hi guys
Had to share this with you ...
This is amazing, have never seen anything like this before in a lightning discharge ( nor has my mate who photo'ed it)
My fellow storm chaser Michael, from NE NSW State of Australia took this photo a few days or so ago

now a closeup

Now tell me that doesn't look like a plasma discharge like you see in those plasma globes ?

is really outstanding

Dave

 

[phinds]

Hm ... I'm thinking some reincarnation of Tesla has a lab down under all that :D

 

[Greg Bernhardt]

Nice! Looks like a cute little lightning bolt!

 

[davenn]

He may have made a new discovery ?

thought it worthy of the Physics Forums :)

 

[Bystander]

Doesn't look like "elf" or "sprite." Spectacular.

 

[Borg]

Very nice Dave. Definitely worthy!

 

[Dotini]

What we are seeing may be a cloud-to-ground "anvil crawler, the horizontal, tree-like, in-cloud lightning discharges whose leader propagation is resolvable to the human eye."
http://stormhighway.com/types.php

PS: I have one of those plasma globes - very amusing!

 

[Bandersnatch]

If you look very closely, you'll notice Zeus at the end of the discharge.

 

[davenn]

Doesn't look like "elf" or "sprite." Spectacular.

No it doesn't as they are usually much larger and well above the storm, without an associated ( directly assoc.) lightning bolt

What we are seeing may be a cloud-to-ground "anvil crawler, the horizontal, tree-like, in-cloud lightning discharges whose leader propagation is resolvable to the human eye."
http://stormhighway.com/types.php

interesting thought but no, this is a cloud to air discharge ... see a little further down the page on that link you gave

I have seen and or photo'ed several in the past, but none of them exhibited this feature

PS: I have one of those plasma globes - very amusing!

yup likewise, great thing to break boredom haha

cheers
Dave

 

[davenn]

That made me giggle, Bandersnatch :)

D

 

[KenJackson]

The main plasma stream is much brighter than the tributaries. But at the top, the brightness suddenly stops. It doesn't seem to decrease in brightness proportionally to current. I wonder why not.

 

[Dotini]

Upward moving lightning from ground to cloud will often tree out into the clouds as it is seen doing here.

 

[davenn]

This isn't from ground to cloud ... its from cloud to clear air ...
have another look at the link you posted earlier and as I then suggested ... scroll down a little :)

Dave

 

[Dotini]

This isn't from ground to cloud ... its from cloud to clear air ...
have another look at the link you posted earlier and as I then suggested ... scroll down a little :)

Dave

Looking at the photo, the lower end of the stroke appears to be obscured by clouds. Are we sure it originates in the lower cloud and not the ground? Above the stroke where the lightning trees into blue branches, it is dark. Is that the sky, or the bottom of another cloud? What are those diagonal streaks going from upper left to lower right in the upper right quadrant of the photo?

Those blue tendrils at the top appear to be mostly discharging into a cloud. The way I see it, this will be upward discharging lightning, either cloud to cloud or ground to cloud, or even intracloud. But not cloud to air.

Cloud-to-Air Lightning
click to enlarge

 

[davenn]

Looking at the photo, the lower end of the stroke appears to be obscured by clouds. Are we sure it originates in the lower cloud and not the ground?

yes, because it would have discharged into the base of the cloud, not gone through and kept going. Also and this is almost the biggest clue
Its obvious the origin point is in the cloud as you can see the intense light from the origin point. In a ground to cloud, that is not usually seen
well at least in the 1000's of lighting discharge pics of my own and of others
And also, there is no lighting (illumination) up of the lower section of the cloud as would happen if the discharge had a path between the cloud and ground ( regardless of the direction)

Those blue tendrils at the top appear to be mostly discharging into a cloud. The way I see it, this will be upward discharging lightning, either cloud to cloud or ground to cloud, or even intracloud. But not cloud to air.

Yes the tendrils are heading towards the cloud
Its an unsuccessful cloud to cloud/intracloud, as the main path ENDS in open air. It just happened to be close enough to the upper part of the cloud to start trying to discharge to the cloud

Here's a pic of my own of a cloud to air, You can also just see a hint of the downwards part of the discharge from the origin point

cheers
Dave

 

[Dotini]

Result of lightning striking a golf course.
https://s.yimg.com/lo/api/res/1.2/5gPp0eNALDShxuPcSjigwA--/YXBwaWQ9eW15O3E9NzU7aD0zNDEuMzMzMzMzMzMzMzMzMzc7c209MQ--/http://slingstone.zenfs.com/offnetwork/cbb5f2387367e2e0a06bffb6b8ff0698
http://ftw.usatoday.com/2016/05/lighting-struck-a-golf-course-in-texas-and-the-results-are-amazing

 

[Dotini]

From today's edition of Spaceweather.com:

RED SPRITES AND GREEN AIRGLOW: Thunderstorm season is underway in the northern hemisphere. That means astrophotographers should point their cameras above the clouds. Thomas Ashcraft did so on June 14th, and he captured two forms of space weather--red sprites and green airglow:

"A large jellyfish sprite appeared over a thunderstorm in the western Oklahoma panhandle last evening," says Ashcraft. "It was about three hundred miles away from my observatory."

"I also caught it in video with very low frequency (VLF) radio emissions, and the parent lightning stroke made a strong pop," he says. Turn up the volume and play the video.

Possibly triggered by cosmic rays, sprites are a form of upper atmospheric that reach up from the tops of thunderstorms toward the edge of space. Although sprites have been seen for at least a century, most scientists did not believe they existed until after 1989 when sprites were photographed by cameras onboard the space shuttle.

The "jellyfish sprite" Ashcraft captured is backlit by a band of green airglow. Airglow surrounds our entire planet, fringing the top of the atmosphere with aurora-like color. Although airglow resembles the aurora borealis, its underlying physics is different. Airglow is caused by an assortment of chemical reactions in the upper atmosphere. Auroras, on the other hand, are ignited by gusts of solar wind.

 

[1oldman2]

RED SPRITES AND GREEN AIRGLOW: Thunderstorm season is underway in the northern hemisphere. That means astrophotographers should point their cameras above the clouds. Thomas Ashcraft did so on June 14th, and he captured two forms of space weather--red sprites and green airglow:

What a lucky shot, thanks for posting that image.

 

[Kevin McHugh]

Fantastic, ain't mother nature grand?

 

[Dotini]

A new model of ball lightning formation which has the advantage of explaining how it can form inside airplanes and pass through windows.

http://www.nature.com/articles/srep28263
Figure 1A: Ball lightning model.

From: Relativistic-microwave theory of ball lightning

(a) Microwave bubble model. (b) Relativistic electron bunch generation. In the last leader step, a bunch of runaway electrons emerges from the leader tip, accelerates by electric fields between the leader and ground, and undergoes an avalanche. (c) Coherent transition radiation (CTR) of the electron bunch striking the ground or passing through aircraft skins. γ is the relativistic factor of electrons.

 

[davenn]

I have yet to see a photo of ball lightning that couldn't be explained by other processes
as in that top photo of yours @Dotini

I was assuming you posted that thinking it was an example of ball lightning ... No
it's just the bright point where the lightning is leaving the cloud and has seriously overexposed
the image with its brightness ... seen that a zillion times

not saying it doesn't exist ... just cannot figure, when there are so many cameras around these days,
why lots of examples don't exist

only other explanation is that it's an extremely rare eventDave

 

[Dotini]

Edit: It is recommended to examine the "Proton Arc Photo Gallery" link at the bottom of the story. It will be seen that most of the "proton arcs" shown have a tightly braided, ropelike structure.

From today's edition of space weather.com:

A MYSTERIOUS FORM OF AURORA: Humans have been watching the aurora borealis for thousands of years, with scientific studies of the phenomenon underway for centuries. Despite all that watching and studying, however, there are still some auroral forms that remain a mystery--namely, the "proton arc." This one appeared over the Grande Cache area of Alberta, Canada, on July 29th:

"As I was driving to the Kakwa river, I saw a purple 'proton arc' crossing the sky from east to west, pulsing and dancing with the Northern lights," says photographer Catalin Tapardel. "Quite a show..."

Aurora photographers see these structures from time to time--tight ribbons of light, sometimes red, sometimes green, writhing across the night sky. They are commonly called "proton arcs."

Yet aurora scientists say they probably have nothing to do with protons.

"My opinion, and I believe the consensus of most aurora scientists, is that these arcs are not proton related, " says Jason Ahrns, a researcher at the University of Alaska Fairbanks, "but I don't know what does cause them."

"Ordinary auroras we see from the ground and space are caused by electrons precipitating down into the atmosphere," says Dennis Gallagher of the NASA Marshall Space Flight Center. "Protons can cause auroras, too, but they are different. For one thing, proton auroras are brightest in the UV part of the spectrum, invisible to the human eye."

There is some visible light from proton auroras, but the structures they make are not tight and filamentary, but rather broad and diffuse--"in part because the gyroradius of protons is large," says Ahrns. In other words, massive protons circle around magnetic fields in broad lazy arcs unlike lightweight electrons, which can tightly circle magnetic fields to form narrow structures.

Ahrns photographed an authentic proton aurora in February 2014: photo. "It appearance matched the description of proton arcs in the scientific literature - 'a dim and diffuse glow' with 'very little structure in the observed brightness' with a total brightness of only a few kiloRayleighs, which is just on the verge of visual threshold (Lummerzheim 2001)."

So what are the "proton arcs" often photographed by amateur aurora chasers? "I don't know," says Ahrns, "but it is something many of us would like to get to the bottom of!" For more examples of this mystery in the sky, browse the Proton Arc Photo Gallery.

 

[1oldman2]

A MYSTERIOUS FORM OF AURORA:

Very very cool, this is entirely new for me. I see a lot of auroras but have never come across this phenomena, ironically this photo

was taken about 50 miles from where I live, thanks for sharing the link.

 

[davenn]

I have photo'ed only one proton arc that I can recall. Many years ago, back when I lived in southern New Zealand
and long before the days of digital cameras. I see then coming up in pic's of those that live in auroral viewable areas of southern NZ and southern Australia ( Sadly, I no longer do )

Another phenomena is one called the picket fence, one that I don't recall having witnessed

The Picket Fence Aurora Australis from Tasmania 15th of August 2015
from Ben Swanson

video here ...

cheers
Dave

 

[1oldman2]

I have photo'ed only one proton arc that I can recall. Many years ago, back when I lived in southern New Zealand
and long before the days of digital cameras. I see then coming up in pic's of those that live in auroral viewable areas of southern NZ and southern Australia ( Sadly, I no longer do )

Another phenomena is one called the picket fence, one that I don't recall having witnessed

View attachment 104189
The Picket Fence Aurora Australis from Tasmania 15th of August 2015

video here ...

cheers
Davefrom Ben Swanson

Totally beautiful, thanks.

 

[Dotini]

Another phenomena is one called the picket fence, one that I don't recall having witnessed

View attachment 104189
The Picket Fence Aurora Australis from Tasmania 15th of August 2015

The "picket fence" reminded of sketches of Carrington event discharges which were said to rise from the horizon to the zenith. Very spectacular!

So I looked up August 15, 2015 on spaceweather.com and found the following entry:

GEOMAGNETIC STORM: Arriving a full day earlier than expected, a CME hit Earth's magnetic field on August 15th (~0800 UT). The impact triggered a strong G3-class geomagnetic storm, now subsiding. Sanjana Greenhill observed these auroras just before sunrise over Anchorage, Alaska:

"The Northern Lights were very bright," says Greenhill.

The CME (movie) that caused the display was propelled toward Earth by a magnetic filament, which erupted on the sun August 12th. A fast-moving solar wind stream is expected to arrive in the wake of the CME. The combined impact of the CME and arrival of the solar wind could energize geomagnetic activity for the rest of the weekend. High-latitude sky watchers should remain alert for auroras. Aurora alerts: text or voice

Realtime Aurora Photo Gallery

GIGANTIC JETS ABOVE HURRICANE HILDA: Yesterday, we reported a rare apparition of sprites above Hurricane Hilda. Steve Cullen, who lives in Hawaii where the storm is heading, spotted them in video from the Canada-France-Hawaii Telescope CloudCam atop Maunakea. A closer look at the video, however, reveals that the dancing forms were not sprites. Instead, Hurricane Hilda has gigantic jets:

Think of them as sprites on steroids: Gigantic jets are lightning-like discharges that spring from the tops of thunderstorms, reaching all the way from the thunderhead to the ionosphere more than 50 miles overhead. They're enormous and powerful.

"Gigantic jets are much more rare than sprites," says Oscar van der Velde, a member of the Lightning Research Group at the Universitat Politècnica de Catalunya. "While sprites were discovered in 1989 and have since been photographed by the thousands, it was not until 2001-2002 that gigantic jets were first recorded from Puerto Rico and Taiwan." Only a few dozen gigantic jets have ever been seen, mostly over open ocean.

Because gigantic jets are so rare, researchers are paying special attention to Hurricane Hilda. "Observations in recent years suggest that large thunderstorm clusters embedded in tropical cyclones harbor favorable conditions for gigantic jets. Hilda seems to confirm this. Extreme turbulent mixing in the storm top may assist in triggering these events," he says.

Gigantic jets, and their cousins the sprites, reach all the way up to the edge of space alongside meteors, noctilucent clouds, and some auroras. This means they are a true space weather phenomenon. Indeed, some researchers believe cosmic rays help trigger these exotic forms of lightning, but the link is controversial.

Stay tuned for more observations of Hilda's cloudtops as it approaches Hawaii.

 

[davenn]

The "picket fence" reminded of sketches of Carrington event discharges which were said to rise from the horizon to the zenith. Very spectacular!

These one as in your pic and stronger ... like standing under a waterfall ... are awesome. I have had a few of them in years gone bye
Google "Coronal Auroral Display" and have a look at the images

There's a lot of pic's there that are NOT coronal displays!. just the typical bands and arcs

These are the ones you want to look at ...

These occur when the auroral oval expands far enough to put you right under the curtain
The biggest one I witnessed was in October 1989 during that solar max. The whole sky was full of rays of light
I have photos but not sure if I have scanned them.

here are some other pix from my old home location ...
http://www.sydneystormcity.com/aurora.htm
cheers
Dave

 

[Dotini]

A lucky shot of rare "gigantic lightning", a discharge from the cloud to the ionosphere.
-from today's edition of spaceweather.com.

http://spaceweathergallery.com/images/spacer.gif

 

[Dotini]

From today's edition of space weather.com:

'A-BOMB' SPRITE OVER THE CARIBBEAN: On Sept. 18th, Frankie Lucena of Cabo Rojo, Puerto Rico, photographed an enormous sprite over the Caribbean Sea. For a split-second, the sky was illuminated by a mushroom-shaped flash:

Oscar van der Velde, a member of the Lightning Research Group at the Universitat Politècnica de Catalunya, explains what Lucena photographed:

"This type of sprite is often called 'jellyfish' or 'A-bomb,' and ranks as the largest type of sprite in both horizontal and vertical dimensions," he says. "It consists of a bright halo approximately 85 km above Earth's surface surrounding sprite elements with long tendrils reaching down as low as ~30 km above ground level."

"This kind of sprite tends to be triggered by a very impulsive positive cloud-to-ground flash," van der Velde adds.

The curious thing is, Lucena did not observe an instigating lightning bolt. Instead, just before the sprite appeared, he recorded a bright point-like flash of light. "Was it a cosmic ray hitting the camera?" wonders Lucena. Play the entire video to see the flash. Another possibility: The point-like flash could have been a cloud-to-ground strike mostly eclipsed by intervening clouds.

If Lucena did photograph something new triggering a sprite, perhaps it shouldn't come as a big surprise. The field is relatively new. Although sprites have been seen for at least a century, most scientists did not believe they existed until after 1989 when sprites were photographed by cameras onboard the space shuttle. There is still much to learn.