On Monday, November 19, 2001, at 12:37 PM, Tim May wrote:
By the way, some calculations are still needed (by basement nuke designers) on what the closing speed needs to be to get a reasonable chain reaction yield. The rough calculations I saw said that a fall from 40 feet, with good tamping behind and all on sides of the masses, would work.
But it would be easy enough to accelerate the falling mass even more. An explosive charge, maybe even a rocket motor.
BTW, there's been a lot of recent work on electromagnetic launchers. Accelerating buckets in tubes, using electromagnets. (Outlined in Heinlein's "Moon is a Harsh Mistress," more than 35 years ago. Also outlined in several recent novels, and of course in technical papers on "mass launch" systems.) An electromagnetic accelerator could accelerate small masses to speeds beyond what explosives could ever accomplish. Imagine the new designs using even less fissionable material (up to certain basic physics limits, of course). Accelerate a small slug of Californium and splat it against a hard target...ah, now _that's_ a basement nuke! --Tim May "The State is the great fiction by which everyone seeks to live at the expense of everyone else." --Frederic Bastiat