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PlaidBastard t1_iznt3ij wrote

I'd argue that boosted fission bombs don't count as 'a-bombs' since they use physics only understood because of huge thermonuclear tests in the 'h-bomb' era. And they use fusion, of literal hydrogen isotopes, even if it isn't a major contributor to the explosive yield.

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RobusEtCeleritas t1_izntbxl wrote

Yes, I agree that boosted weapons are technically "thermonuclear" too, just with a much smaller amount of fusion fuel. I don't think the common terminology is good, but this is what it is.

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sault18 t1_iznwfbe wrote

And don't boosted weapons use fusion mostly just to generate neutrons to cause fission fast enough before the device blows itself apart?

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RobusEtCeleritas t1_iznww1y wrote

Yes, but the same could be said of many "true thermonuclear" weapons too. The main contribution of the fusion fuel to the yield is due to the high-energy fusion neutrons inducing more fission, rather than the fusion reaction Q-values, which are on the order of 10 times lower than the relevant fission Q-values.

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[deleted] t1_izntxp2 wrote

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RobusEtCeleritas t1_iznu6lf wrote

Modern designs are all thermonuclear (fully thermonuclear, not just boosted fission). But not all countries have modern stockpiles. So we still need words to refer to old designs and differentiate them from modern ones.

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[deleted] t1_izntwmg wrote

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RobusEtCeleritas t1_iznuh96 wrote

All nuclear weapons use fission in some way. Even "pure fusion" weapons are not really pure fusion.

Reaching a state where a thermonuclear burn can take place, outside of stars and certain scientific research devices, requires fission.

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meme_slave_ t1_iznwitd wrote

Correct me if i am wrong but there aren't any "pure fusion" bombs, to achieve that you'd need to somehow use conventional explosives to heat deuterium and tritium to a couple hundred million degrees and ridiculous unachievable bar.

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RobusEtCeleritas t1_iznx823 wrote

Yes, that's what I was saying. There are weapons that are loosely referred to as "pure fusion", but they don't actually purely consist of fusion fuel. Some amount of fission fuel is needed to ignite the thermonuclear burn of the fusion fuel.

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