4 ms·

Microwaves trapped in balls of plasma. Electrons accelerated fast enough to pass through sheet aluminum, but able to slow down and form a ball on the other side

Microwaves trapped in balls of plasma. Electrons accelerated fast enough to pass through sheet aluminum, but able to slow down and form a ball on the other side. Electrons accelerated to high relativistic speeds, producing nothing more potent than mere microwaves when decelerated. I am no physicist, but these explanations seem really messed up. I don't think this guy got us any closer to understanding ball lightning.

laughinghan 10y ago
None of that sounds implausible to me. • Plasma is opaque to electromagnetic radiation (including microwaves), it could totally be trapped: https://www.reddit.com/r/askscience/comments/26jxu6/why_is_plasma_opaque_to_radiation/ https://www.reddit.com/r/askscience/comments/26jxu6/why_is_p... • Beta radiation (electrons) are known for passing through several millimeters of aluminum (³²P beta radiation penetrates to a depth of 3/8th of an inch or 9.5mm): http://www.alpharubicon.com/basicnbc/RadiationPenetration.htm http://www.alpharubicon.com/basicnbc/RadiationPenetration.ht... Besides, radiation penetration isn't discrete, it's an exponential falloff; even if only 0.1% makes it through a particular sheet of aluminum, well, one thousandth of a lightning strike is still a serious amount of radiation. • If you've ever sat in front of a CRT TV or computer monitor, electrons were accelerated to relativistic speeds right at your face in the span of a foot or so, about 1/3 c: https://au.answers.yahoo.com/question/index?qid=20101101030617AAGm7aD https://au.answers.yahoo.com/question/index?qid=201011010306... Maybe 1/3 c doesn't count as "high relativistic" in your book, but clouds are huge compared to CRT monitors, any free electrons would be in much stronger electric fields and would be accelerating over much greater distances.
- rcthompson 10y ago
  I don't doubt that lightning launches electrons at high speed. I doubt that those electrons can pass through a metal sheet at high speed and then immediately come to a stop on the other side before travelling the dozen or two feet across the plane and out the other side.
  - pmalynin 10y ago
    Plus rapidly decelerating electrons produce x-rays.
    - laughinghan 10y ago
      "For high atomic number materials, there is a chance of the beta particles loosing energy by producing some x-rays. In water, the x-ray production from a beta particle is quite miniscule." http://www.alpharubicon.com/basicnbc/RadiationPenetration.htm http://www.alpharubicon.com/basicnbc/RadiationPenetration.ht... By "high atomic number materials" they mean stuff like lead, 82. Aluminum is 13.
    - InclinedPlane 10y ago
      You didn't read the paper.
  - laughinghan 10y ago
    They can't maintain high speed for long. "The charge of the beta particle will continuously cause ionization along the path that it is traveling. Because of this, when a beta particle enters some material, it begins slowing down, and slows down continuously." Same link as above: http://www.alpharubicon.com/basicnbc/RadiationPenetration.htm http://www.alpharubicon.com/basicnbc/RadiationPenetration.ht...
InclinedPlane 10y ago
Did you read the paper at all? It's pretty accessible. The main component is ultra high energy microwaves, these are generated by relativistic electrons accelerated beyond the front of the step leader before it hits the ground. When those electrons penetrate through matter they can release microwaves as they decelerate. They can also cause ionization of the air as well. And these phenomena feed off one another. The microwave radiation then gets trapped inside a bubble of plasma as a standing wave. This is a quasi-stable phenomenon because the microwave energy heats the plasma and thus maintains its own confinement. Interestingly, this model seems to explain the vast majority of observational evidence related to ball lightning, including some of the more bizarre occurrences. It's also testable. The easiest way to test it would be making use of 100GW class microwave emitters, which are just a touch beyond the state of the industry today but should be available soon. And that should make it possible to determine the accuracy of the theory and, if it proves accurate, to further study the properties of ball lightning.
- happyslobro 10y ago
  > 100GW class microwave emitters Those exist, but they just aren't commercially available yet? Dude, pics! That's like an Akira class orbital ion cannon, no?
  - wycx 10y ago
    I thought similarly, and did some searching and found this: https://en.wikipedia.org/wiki/KALI_(electron_accelerator) https://en.wikipedia.org/wiki/KALI_(electron_accelerator)
    - happyslobro 10y ago
      > There is also speculation of using the KALI as an anti-satellite weapon and as a space-based weapon system, although it is unlikely... "AKIRA!!!"

laughinghan 10y ago

None of that sounds implausible to me. • Plasma is opaque to electromagnetic radiation (including microwaves), it could totally be trapped: https://www.reddit.com/r/askscience/comments/26jxu6/why_is_plasma_opaque_to_radiation/ https://www.reddit.com/r/askscience/comments/26jxu6/why_is_p... • Beta radiation (electrons) are known for passing through several millimeters of aluminum (³²P beta radiation penetrates to a depth of 3/8th of an inch or 9.5mm): http://www.alpharubicon.com/basicnbc/RadiationPenetration.htm http://www.alpharubicon.com/basicnbc/RadiationPenetration.ht... Besides, radiation penetration isn't discrete, it's an exponential falloff; even if only 0.1% makes it through a particular sheet of aluminum, well, one thousandth of a lightning strike is still a serious amount of radiation. • If you've ever sat in front of a CRT TV or computer monitor, electrons were accelerated to relativistic speeds right at your face in the span of a foot or so, about 1/3 c: https://au.answers.yahoo.com/question/index?qid=20101101030617AAGm7aD https://au.answers.yahoo.com/question/index?qid=201011010306... Maybe 1/3 c doesn't count as "high relativistic" in your book, but clouds are huge compared to CRT monitors, any free electrons would be in much stronger electric fields and would be accelerating over much greater distances.

rcthompson 10y ago
I don't doubt that lightning launches electrons at high speed. I doubt that those electrons can pass through a metal sheet at high speed and then immediately come to a stop on the other side before travelling the dozen or two feet across the plane and out the other side.
- pmalynin 10y ago
  Plus rapidly decelerating electrons produce x-rays.
  - laughinghan 10y ago
    "For high atomic number materials, there is a chance of the beta particles loosing energy by producing some x-rays. In water, the x-ray production from a beta particle is quite miniscule." http://www.alpharubicon.com/basicnbc/RadiationPenetration.htm http://www.alpharubicon.com/basicnbc/RadiationPenetration.ht... By "high atomic number materials" they mean stuff like lead, 82. Aluminum is 13.
  - InclinedPlane 10y ago
    You didn't read the paper.
- laughinghan 10y ago
  They can't maintain high speed for long. "The charge of the beta particle will continuously cause ionization along the path that it is traveling. Because of this, when a beta particle enters some material, it begins slowing down, and slows down continuously." Same link as above: http://www.alpharubicon.com/basicnbc/RadiationPenetration.htm http://www.alpharubicon.com/basicnbc/RadiationPenetration.ht...

InclinedPlane 10y ago

Did you read the paper at all? It's pretty accessible. The main component is ultra high energy microwaves, these are generated by relativistic electrons accelerated beyond the front of the step leader before it hits the ground. When those electrons penetrate through matter they can release microwaves as they decelerate. They can also cause ionization of the air as well. And these phenomena feed off one another. The microwave radiation then gets trapped inside a bubble of plasma as a standing wave. This is a quasi-stable phenomenon because the microwave energy heats the plasma and thus maintains its own confinement. Interestingly, this model seems to explain the vast majority of observational evidence related to ball lightning, including some of the more bizarre occurrences. It's also testable. The easiest way to test it would be making use of 100GW class microwave emitters, which are just a touch beyond the state of the industry today but should be available soon. And that should make it possible to determine the accuracy of the theory and, if it proves accurate, to further study the properties of ball lightning.

happyslobro 10y ago
> 100GW class microwave emitters Those exist, but they just aren't commercially available yet? Dude, pics! That's like an Akira class orbital ion cannon, no?
- wycx 10y ago
  I thought similarly, and did some searching and found this: https://en.wikipedia.org/wiki/KALI_(electron_accelerator) https://en.wikipedia.org/wiki/KALI_(electron_accelerator)
  - happyslobro 10y ago
    > There is also speculation of using the KALI as an anti-satellite weapon and as a space-based weapon system, although it is unlikely... "AKIRA!!!"