Naked Science Forum
General Science => General Science => Topic started by: paul cotter on 03/05/2022 20:11:44
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In the nuclear weapon tested at the trinity site two explosives with different velocities of detonation were moulded into carefully designed shapes to produce a perfect spherical shockwave on the metals of the core.If a sphere of homogenous explosive were initiated simultaneously at all points on the surface would this produce a spherical shockwave?.This is something that could not be achieved in practice as it would require an infinite number of infinitesimal detonators.
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It would be pointless but...
imagine getting a balloon full of a mixture of hydrogen and oxygen.
Then put a UV emitting LED in the middle of it, and then enclose it in another balloon, full of a mixture of hydrogen and chlorine.
If you switch the LED on it will emit UV light and that will pass straight through the inner balloon but it will be absorbed by the chlorine and initiate an explosion.
And that will initiate the explosion of the inner balloon, from all over its surface at the same time.
So that should give an inbound spherical explosion.
If the outer balloon is only a bit bigger than the inner one, you can get a very good approximation to simultaneous initiation with a bright flash from the outside if you surround it with mirrors and have a few flashbulbs in series.
And, in principle, you can use that to trigger a spherical implosion in something more powerful than air + H2.
I doubt it would work, but I can't see why not.
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The Trinity test didn't need a perfectly spherical implosion - just good enough.
- And it worked - but they needed a much more compact arrangement if they were to fit it into a plane.
https://en.wikipedia.org/wiki/Trinity_(nuclear_test) (https://en.wikipedia.org/wiki/Trinity_(nuclear_test))
Another area trying to do spherical implosions today is the US National Ignition Facility, which is trying to initiate nuclear fusion with a spherically symmetrical arrangement of 192 lasers.
See: https://en.wikipedia.org/wiki/National_Ignition_Facility#Tests_and_construction_completion
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I believe it had to be of very good symmetry. High explosives regularly produce pressures of 400kbar. In a spherical implosion pressures can be in the 10-50Mbar. Under these conditions the large uranium tamper and plutonium at the centre are in the liquid state and any significant asymmetry will lead to material squirting out and loss of criticality.