I Nuclear Explosion in Space… How would it work?

Drakkith

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What do you mean?
If you have linear relation between heat and damage then you are right. In fact, the pulse heat (IR/visible/UV) damage is demonstrating saturation - due ablation effects. To say simple, over-powered heat pulse spend most of its energy over threshold to heat smoke emitted from exposed surfaces, and therefore mostly wasted.
My response is poorly worded ... the damage level is "saturated". The key takeaway for me is that the energy and damage really have to be parsed separately. Although the shockwave energy may show up in another damage ... it may be also be lost completely. My initial thinking was that the shockwave energy would show up at least partly as increased heat damage.
 

Drakkith

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My response is poorly worded ... the damage level is "saturated". The key takeaway for me is that the energy and damage really have to be parsed separately. Although the shockwave energy may show up in another damage ... it may be also be lost completely. My initial thinking was that the shockwave energy would show up at least partly as increased heat damage.
My mistake. I completely missed that you quoted trurle's post.
 

pinball1970

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where are you getting these figures from ??
Yes what is waving? A shock wave on the earth is air molecules what is waving in the vacuum of space?
 

Mark Harder

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I doubt that there would be any shockwave ... a shockwave is a mechanical wave (like a sound wave) it needs a medium to travel in
Unless it was set off in the middle of a gaseous mass aka a nebula or a planetary atmosphere, or a dense part of the asteroid belt etc, there would be no shock wave Dave
Except that the bomb itself will be vaporized, and since only a small fraction nuclear fuel is consumed in an explosion, most of the initial mass of the bomb will be ejected. I would think the vapor would initially be a plasma, which will cool as it expands, potentially giving electrons and nuclei the opportunity to recombine recreating the original atoms. When the electrons fall out of the continuum, the energy they lose will be emitted as radiation in excess of the prompt radiation from the fission reactions. Would all of that matter form a shock wave, albeit a weaker one than that which would form on Earth? Since electrons are much less massive than nuclei - especially the nuclei of heavy atoms like uranium - they would outpace the nuclei, so the atoms wouldn't be able to recombine. In that case, I would expect that there would be a 'shock wave' of electrons followed by a true shock wave of heavy nuclei. A thermonuclear weapon would eject helium in the form of alpha particles and and electrons, unburned hydrogen in the form of protons and electrons, and perhaps some lithium. However, these wouldn't carry the same kinetic energy as the actinides. I suppose one could always pack the warhead with extra mass that would increase the density of the plasma, increasing the punch of the shock wave.
 
Here are two partially declassified old (1960s) films used by the US to train military personnel:

"High Altitude Nuclear Weapon Effects • Part One • Phenomenology"


"High Altitude Nuclear Weapon Effects • Part Two • Systems Interference"


These are indeed "blasts from the past".
 
I don't get this 65% reduction. The total released energy is still the same. So the energy that didn't go into the shock-wave, must go somewhere else, like radiation. But it cannot just disappear.
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Total released energy from detonation in the vacuum of space would typically be less than the total released energy from detonation well within the atmosphere, mainly due to the pressure and mass of the atmosphete acting as a tamper effectively delaying disassembly allowing additional fissions and fusions to occur.
Additionally, surrounding atmosphere will act to some very limited degree as a neutron reflector, sending some otherwise escaped neutrons back through for another pass at the fissile material in the "spark plug", casing and disassembling originally supercritical mass to increase fission yields, as well as with lithium to produce additional tritium and He3 production to increase fusion yield.
There would also be the effect of differing heat transfer rates immediately following detonation. Heat transfer being dominated by radiation in a very short period immediately following detonation and the lack of atmosphere forming an opaque barrier to many wavelengths at very high temperatures, the disassembling device will experience greater heat transfer briefly after detonation causing temperatures to fall more quickly shortly after detonation making conditions for fusion less favorable that those for a detonation in atmosphere.
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As to a 'shockwave'developing, what occurs in the vacuum of space is going to be very different for what occurs in the atmosphere. Not having the resistance of the atmosphere, the fastest particles will attain higher speeds. Without atmospheric resistance, outward bound material does not slow much until it has something to interact with. Without atmospheric resistance, there will be no coalescence into a leading edge shock front. The fastest particles will continue to move further ahead of the slower particles. At sufficient distance particles from the blast will be effectively segregated into a smooth gradient of speed with the particles with greatest speed arriving first and successively slower particles arriving there after.

I too am suspicious of the '65%' reduction in damage because it would need to treat all the various types of damage as fungible across various targets and this is simply not the case. Damage from various effects is heavily dependent on the type of target, so altering the relative strength of such effects would require specification of target type to begin to compare relative damage.
 
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