What is the smallest possible nuclear weapon and what are its potential uses?

[Eridanus1]

What is the biggest explosive potential of a nuclear weapon? Is it a deuterium-tritium based chain reaction or something more advanced than that?

If the film 'Independence Day' became real, what could we use to zap the alien ships? What is the ultimate destructive weapons at our disposal in this era?

thnx,
Eridanus1

 

[Astronuc]

Browse there for some information.

http://www.vce.com/tsar.html

http://nuclearweaponarchive.org/Russia/TsarBomba.html

http://en.wikipedia.org/wiki/Tsar_Bomba

The US and others stopped looking at large thermonuclear devices and have instead focussed on smaller MIRVs.

 

[Mk]

Wow, that Tzar Bomba is a freakin big ass bomb.

 

[Eridanus1]

I hope we never hsve to use it... on our fellow mankind (pacifist!)

Eridanus1

 

[arivero]

Eridanus1, there was also the project "plowshare": the use of nuclear weapons in civil works.

 

[ohwilleke]

I have to agree that the question of what is the smallest possible nuclear weapon (strictly speaking more of an engineering question) is more interesting than the largest possible one. There is very little need to blow up an entire country with one weapon, as opposed to the several hundred that will do the job now. In contrast, there are numerous military applications for very small but potent weapons (so called "tactical nuclear weapons"), although whether or not this is prudent is another question.

This source reports that the smallest nuclear weapon made by the U.S. was a little less than 25 kg and had a 10 ton to 1 kiloton yield. It suggests that it is possible that nuclear weapons in the 1kg to 4kg range may have been made.

http://www.tinyvital.com/Misc/nukes.htm