[Breaking] North Korea tests Hydrogen Bomb

Regarding the smaller than expected result:

A "hydrogen bomb" is a fusion bomb. The way you create enough energy for fusion is by setting off a fission bomb, (like the ones North Korea has already made or like the bombs the USA used on Japan) which then triggers a second, larger, fusion reaction. Basically, you take the kind of bomb that North Korea already knew how to make, and then strap an apparatus on to it, which uses the energy of the first explosion in the form of x-rays to set off an explosion that is orders of magnitude larger. The standard design is called "Teller–Ulam" after the physicist and mathematician (respectively) who first designed it.



If there was a big explosion, but not big enough to be a "hydrogen bomb", it seems most likely to me that the fission bomb first explosion went off as expected, which is something they already knew how to do, but the second part - the fusion part - didn't work.

From Wikipedia, the first unequivocally successful bomb test they had in 2009 measured 5.3 in Japan. There is a ton going on there with physics and geology and whatever else that I don't know anything about, but I think it is reasonable to guess that similar tremor = similar magnitude explosion. So it sounds like North Korea's first stage of the bomb worked, and the second, fusion part - the part that they are bragging about, was a dud.

Still better than I could do, but presumably not as intimidating as I think they were hoping for. It sounds like they didn't show any new capabilities at all, though I'm sure they'll keep working on it. Supposedly, their first ever test of the earlier fission device was a semi-dud, and they seem to have figured out the process.

Now that I think about it, I think a hydrogen bomb requires plutonium, whereas a fission bomb can work with only uranium, so maybe they demonstrated an ability to create plutonium in their reactors from uranium? Maybe that is something new.

 

I had to look this up. FWIW: the energy in the Hiroshima blast was equivalent to a 6.0 earthquake, which was a small fission bomb, and almost 10x more than a 5.1 earthquake.

Of course, these comparisons assume the explosion was underground enough to maximize its energy readings on seismic-measuring devices.

 

With this new development I think I should be allowed to have a W87 MIRV for protection.

 

They still can't fly them out of their backyard.

What's to worry.

I'd be more afraid if I were a resident of N.Korea.

 

Great Leader Kim no lie. He tell truth all time. American pig try make Great North Korea look stupid. #Thank



(You all must follow Kim Jong Un on Facebook. It is simply amazing.)

 

<blockquote class="twitter-tweet" lang="en"><p lang="en" dir="ltr">Experts doubt North Korea’s claims of successful H-bomb test - <a href="https://twitter.com/RichardEngel">@RichardEngel</a> <a href="https://t.co/9RYmAUwU6D">https://t.co/9RYmAUwU6D</a></p>&mdash; NBC Nightly News (@NBCNightlyNews) <a href="https://twitter.com/NBCNightlyNews/status/684894730593763328">January 7, 2016</a></blockquote> <script async src="//platform.twitter.com/widgets.js" charset="utf-8"></script>

 

What exactly is NK's beef?

 

Talked to my friend who lives in Seoul to ask how everyone reacts to news like this, and he says that no one in that country takes what North Korea does seriously.

He says that they pull stunts like this when they're running short on supplies and money in the country. Other countries see this, worry, and then cave into the requests of shipping in more food and resources.

I guess they're running low on their ****.

 

That's what I came here to post.

 

Dog meat, they can't afford beef.

 

http://www.bloomberg.com/news/artic...ict-k-pop-blasts-on-kim-jong-un-for-nuke-test

 

Not sure if anybody still cares, but the suggestion I've seen is that this was probably a "boosted fission bomb", which one could technically argue was a "thermonuclear" bomb, even though it doesn't increase the yield over "normal" kiloton-range "A bomb" yields.

https://en.wikipedia.org/wiki/Boosted_fission_weapon

My crappy explanation:

Nukes blow nuclear because the atoms of radioactive material release neutrons, which hit other atoms, which release neutrons of their own, and so on. It is sort of a "cascade" where you get so many neutrons flying around in a small place that all the nuclear material in that place is being bombarded with neutrons as the same time, causing it to all react simultaneously. Conventional explosives are used to press the fission material together into a small enough space to accelerate neutron collisions - jam more stuff into the same spot makes it likely that released neutrons will hit other atoms.

Supposedly, when you shrink the bomb down small enough to fit on a warhead, you start to have problems with the explosion of the conventional explosives physically blowing the nuclear core to pieces before the neutron cascade really gets started. Think the difference between a big heavy vault door on a safe slamming shut slowly with lots of effort and a light plywood cabinet that will bounce back if you tap it closed with too much force.

So historically, the answer has been to add gasses that undergo fusion - tritium and deuterium. These gasses don't add much at all to the reaction's total energy, but when they fuse, they release neutrons which add to the flux of the fission bomb. As a result, more neutrons means that the supercritical cascade state is achieved more quickly. You ensure that the uranium/plutonium are actually consumed in the supercritical nuclear reaction before they have a chance to be blown apart by conventional explosives.

Technically, because it uses tritium and deuterium, fusion is involved and one could technically argue that it is "thermonuclear", even though those don't add noticeably to the output energy of the bomb (1% of total energy), in the way that one traditionally thinks of "thermonuclear" bombs.

It would be a problematic in two parts, though. First, it would indicate miniaturization, as for mounting on a warhead. Secondly, the miniaturization would be the first step to building what everybody thinks of as a "thermonuclear bomb" - the large cumbersome "fat man" type devices don't work well with a second fusion stage attached.

At least, that is what I've been able to gather in the last day or so.

In other words, this is probably a thing, and not just another reason to laugh at the stupid North Koreans.

 

thx Ottomaton