metalresearcher
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A mini Sun from plasma or ... Polonium ?
Just a fantasy as such experiments cannot be performed as an amateur chemist. In a large professional lab like LANL or National Ignition Facility it
would be possible.
I was thinking of how the Sun would be when downscaled 1 billion times.
That would result in a large skippy ball of 1.4m diameter and on a distance of 150m it would shine just like the real Sun. Same angular diameter and
same brightness. According to the Boltzmann law the surface temperature of that skippy ball would be the same 5700K, thus scorching everything within
a few tens of meters. The power would be (the Sun is 3.8e26 W) 3.8e26/(1 billion)^2 = 380e8 W = 380MW.
From plasma or radioactive elements. Polonium is such a candidate. According to world's largest chemistry textbook, Po-210 emits 140 W per gram, so to get 380 MW one needs to have 2.7 tons of Po which is infeasible as only 100
grams a year are produced, mostly in Russia.
Downscaling another 100 times would shrink the ball to 1.4cm diameter, emitting 380e6/(100^2) = 38kW which is within reach.
Such a ball of 14mm diameter of Po weighs 13 grams. That yields 13*140W = 1.8kW so far less than the downscaled Sun. But, according to Boltzmann's
law, the surface temperature of that ball will yet be ((1800/38000)^1/4)*5700 = 2700 K == 2400 C. Far too hot to keep Po in solid or liquid state. But
within a container of Ir, Ta or even WC or diamond it will remain solid. Not like a mini-Sun, but a mini red dwarf.
But is there any material (probably plasma as no solids exist at 5400 C, unless at Earth's core pressures) to make such a mini-Sun ?
Or a radioisotope which emits more power per volume ? I think Po-210 has the highest energy density.
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Sulaiman
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Wikipedia: Po, m.p. = 254C, b.p. = 962C
so you'd be dealing with one of the most toxic substances on earth in the vapour phase 
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PHILOU Zrealone
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Maybe a stupid remark, but hasn't Polonium a critical mass (like other very radioactive materials) at what it does start the cascade nuclear chain
reaction?
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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wg48
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The sun only produces a few watts per m^3. (from memory) Thats less than a compost heap.
I think you forget the cube factor in your calculation.
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Bert
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Quote: Originally posted by PHILOU Zrealone  | | Maybe a stupid remark, but hasn't Polonium a critical mass (like other very radioactive materials) at what it does start the cascade nuclear chain
reaction? |
You need a Be target to be hit by alpha particles Po decay releases in order to generate neutrons, as in the "urchin" or "screwball" neutron sources
of early fission weapons- Po is not fissile in and of itself.
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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metalresearcher
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| Quote: Originally posted by wg48 | The sun only produces a few watts per m^3. (from memory) Thats less than a compost heap.
I think you forget the cube factor in your calculation. |
That is right.
But I assumed the same brightness on the same scaled distance, hence the square factor.
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careysub
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Make a gas core fission reactor- this could have the necessary power density.
Of course the temperature of the sun is above the melting point of any known material, so how it would be built is mysterious. Usually proposals for
such devices assume it is contained in a magnetic field, but it would then be surrounded by a containment structure housing the field coils, with free
radiation only in one direction.
But the "decay sun" has the same problem, plus the problem of producing an implausibly large amount of a short-lived nuclide.
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