Would a HEMP event cause the northern lights?

[thisisweak]

Hello, I looked everywhere and elsewhere for an answer to this. And I can't seem to find an answer. If a High-altitude Electromagnetic Pulse was detonated, Would this set off the Northern Lights?

While a solar flair is due to a stream of electrons and ions(I hope that I got that correct). A HEMP is an event from a cascade of electrons. Not sure what they mean by cascade there.

Anyway from what I have read, the Northern lights occur with collisions with oxygen molecules about 60 miles (or about 96 km as I am sure you prefer). It just seems both events have enough in common to produce some of the same effect.

 

[davenn]

While a solar flair is due to a stream of electrons and ions(I hope that I got that correct).

not quite ... a solar flare is one cause/source of a burst of charged particles from the sun ... see my comments in your other thread on this topic. A stream of charged particles do not cause a flare.

If a High-altitude Electromagnetic Pulse was detonated, Would this set off the Northern Lights?

A HEMP is an event from a cascade of electrons. Not sure what they mean by cascade there.

Not really familiar with that topic ... maybe a really good idea to give some links to what you have been reading so that we can all be on the same page.
Jf there are a burst of electrons from a HEMP event, then the HEMP would have to be ...
1) Very high altitude to be able to push those electrons into the Earth's magnetic field
2) probably close to one of the geomagnetic poles so that the electrons would have the best chance of getting trapped in the magnetic field so as to produce an auroral event
Dave

 

[marcusl]

Yes. Following a high altitude detonation, the electrons that are knocked loose in the ionosphere due to the Compton effect, and which cause the EMP, can then travel long distances while spiraling around the Earth's magnetic field lines. Where the lines dip down into the atmosphere to re-enter the earth’s crust, the energetic electrons ionize nitrogen and oxygen atoms in the tenuous atmosphere, causing an aurora. This occurs both to the north of the detonation (if in the northern hemisphere) and, later, at the opposing spot in the southern hemisphere. Wikipedia has a nice explanation of the phenomenology under the second section heading here
https://en.wikipedia.org/wiki/Operation_Fishbowl

 

[thisisweak]

Thank you! Great explanation.

By the way, with help from your link I found some declassified video of the event(s). It does indeed create a fishbowl. Personally, I think a better description would be to classify it as a dome. This video shows many of the high atmospheric explosion tests performed by the United States. I really recommend watching them since they are really different from land or sea based tests.