Why did the US build a hydrogen bomb?

Answer 1

Most Western Nations were surprised at how quickly the USSR was able to create their own fission (atomic) bomb. So instead of enjoying 5-10 years of atomic superiority, Western Countries were now looking at an unexpected threat.

By pushing the development of the fusion (hydrogen) bomb, it was hoped that Western Countries could once again gain weapon superiority.

Answer 2

The US built the hydrogen (fusion) bomb for several reasons, most of them parallel to the reasons why the US had earlier built the atomic (fission) bomb:

• The general physics required to do so were well known in the world physics community. [fusion: solar/stellar fusion physics fission: discovery of uranium fission by neutrons and chain reaction]
• A political/war situation resulting in great fear that if we did not do it first, an enemy might and then use them against us or our allies. [fusion: cold war and Korean War fission: nazi Germany and WW2]
• The discovery of the key physical process (x-ray radiation implosion) needed to make them reliable and efficient. This was discovered by the mathematician Stanislau Ulam in work on raising the efficiency of existing fission bomb designs and improved on by Edward Teller when he realized it was the feature missing from all his earlier fusion bomb designs (that computer simulation showed would fail). This design feature is now known as the Teller-Ulam Configuration. [fusion: x-ray radiation implosion fission: implosion assembly with explosive lenses]
• etc.

The first fusion bomb built was in 1952, the 80 foot tall 20 foot in diameter cryogenically cooled liquid deuterium-tritium fueled Ivy Mike test shot.

Answer 3

The US tested the hydrogen (fusion) bomb in the 1952 Ivy Mike test shot for exactly the same reasons it tested the atomic (fission) bomb in the 1945 Trinity test shot:

• The design was too complex to verify on the computers available at the time.
• The design depended strongly on the exact timing of many very fast events that could not be verified in small scale component tests.
• Even if computers of the time could have done the calculations, many crucial physical constants needed to get a valid answer had not yet been measured with enough accuracy.
• etc.

Answer 4

It was an idea of Enrico Fermi at first, as part of the Manhattan Project, but was later developed most likely for war and protection reasons.

Answer 5

Fear of US nuclear weapons.