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> This design is called the Teller-Ulam design, and it is extremely likely that it was discovered only once (by Ulam and Teller), all other thermonuclear bombs

> This design is called the Teller-Ulam design, and it is extremely likely that it was discovered only once (by Ulam and Teller), all other thermonuclear bombs are just the result of successful spying and secret sharing. Hans Bethe believed that the Soviets and the British got it by analyzing the fallout from fusion bomb tests. Apparently the high number of heavy elements suggested high rates of compression

credit_guy 3y ago
Hans Bethe guessed based on the information available to him at the time. But there was information not available to the West prior to the end of the Cold War. In December 1991 two US atomic scientists, Danny Stillman and Nerses Krikorian visited the head of the former Soviet nuclear program, Yuliy Khariton [1]. In their discussions, the Americans realized that even Khariton was not aware of the extent of the Soviet spying. In any case, Khariton had a very dubious recollection of who came up with the idea of the radiation implosion (the Teller-Ulam design). This was such an ingenious idea that if it had indeed originated with one of the Soviet scientists, it would have been memorable. By the way, the Soviets did come up with a thermonuclear design, dubbed "layer cake" in the US. But it was an inferior design that resulted in a yield of only 400 kT (the RDS-6 test [2], in August 1953), which was achievable with fission only. In March 54 the US detonated a few hydrogen bombs, and indeed, the Soviets collected radioactive debris. However, Khariton told Stillman that that information was not helpful, aside from the confirmation that higher yields are somehow possible. Throughout the month of March 1954 the Soviets played with a few ideas, but none was good. Then, miraculously in mid-April 1954, Khariton claims that his deputy Yakov Zeldovich [3] came up with the idea of radiation implosion. But other Soviet nuclear scientists that Stillman and Krikorian interviewed stated that they never heard Zeldovich confirm that story. Moreover, one of these scientists , Lev Feoktistov stated quite candidly "We had neither drawings nor accurate data from the outside, but we were prepared to catch hints and half-hints. I can't shake the feeling that in those times, we were not completely independent" Stillman put all these things (and quite some more) in a book, The Nuclear Express [4]. [1] https://en.wikipedia.org/wiki/Yulii_Khariton https://en.wikipedia.org/wiki/Yulii_Khariton [2] https://en.wikipedia.org/wiki/Joe_4 https://en.wikipedia.org/wiki/Joe_4 [3] https://en.wikipedia.org/wiki/Yakov_Zeldovich https://en.wikipedia.org/wiki/Yakov_Zeldovich [4] https://www.google.com/books/edition/The_Nuclear_Express/qLTuAAAAMAAJ?hl=en https://www.google.com/books/edition/The_Nuclear_Express/qLT...

credit_guy 3y ago

Hans Bethe guessed based on the information available to him at the time. But there was information not available to the West prior to the end of the Cold War. In December 1991 two US atomic scientists, Danny Stillman and Nerses Krikorian visited the head of the former Soviet nuclear program, Yuliy Khariton [1]. In their discussions, the Americans realized that even Khariton was not aware of the extent of the Soviet spying. In any case, Khariton had a very dubious recollection of who came up with the idea of the radiation implosion (the Teller-Ulam design). This was such an ingenious idea that if it had indeed originated with one of the Soviet scientists, it would have been memorable. By the way, the Soviets did come up with a thermonuclear design, dubbed "layer cake" in the US. But it was an inferior design that resulted in a yield of only 400 kT (the RDS-6 test [2], in August 1953), which was achievable with fission only. In March 54 the US detonated a few hydrogen bombs, and indeed, the Soviets collected radioactive debris. However, Khariton told Stillman that that information was not helpful, aside from the confirmation that higher yields are somehow possible. Throughout the month of March 1954 the Soviets played with a few ideas, but none was good. Then, miraculously in mid-April 1954, Khariton claims that his deputy Yakov Zeldovich [3] came up with the idea of radiation implosion. But other Soviet nuclear scientists that Stillman and Krikorian interviewed stated that they never heard Zeldovich confirm that story. Moreover, one of these scientists , Lev Feoktistov stated quite candidly "We had neither drawings nor accurate data from the outside, but we were prepared to catch hints and half-hints. I can't shake the feeling that in those times, we were not completely independent" Stillman put all these things (and quite some more) in a book, The Nuclear Express [4]. [1] https://en.wikipedia.org/wiki/Yulii_Khariton https://en.wikipedia.org/wiki/Yulii_Khariton [2] https://en.wikipedia.org/wiki/Joe_4 https://en.wikipedia.org/wiki/Joe_4 [3] https://en.wikipedia.org/wiki/Yakov_Zeldovich https://en.wikipedia.org/wiki/Yakov_Zeldovich [4] https://www.google.com/books/edition/The_Nuclear_Express/qLTuAAAAMAAJ?hl=en https://www.google.com/books/edition/The_Nuclear_Express/qLT...