This is really quite delightful, and I feel like a terrible killjoy for pointing out that your magical nuclear fusion analysis has several problems....
The first is that you haven't really looked at how to heat the rock to T_C. You've calculated the required density needed to get your estimated Coulomb Pressure, assuming the temperature is (somehow) T_C. So how do we go from room-temperature rock to a 3 GK plasma? Rapidly forcing all that rock into a smaller volume *will* heat it up, of course, and maybe you could approximate that as an adiabatic process? (I think the problem might actually be that you pass T_C long before you reach your estimated critical density.)
The second is that silicon burning is *not* actually the fusion of two Si nuclei, so the Coulomb Pressure and critical density calculations are irrelevant. Silicon burning is a complex set of reactions based around the photodissociation of Si (and other) nuclei by gamma rays and subsequent reactions involving the interactions of the protons, neutrons, and alpha particles liberated by the Si (etc.) photodissociation.
(As it happens, the density of a stellar core undergoing silicon burning is more like 10^8 g/cm^3, so you've probably significantly overestimated the number of Enlarge spells needed.)
The third problem is that the plasma will rapidly cool down due to all the photons leaking out through the force wall (it's invisible, after all!), so I suspect that if you *do* get nuclear-burning reactions started, they won't last very long.
And in fact they really won't last very long, because the final problem is that the leakage of thermal photons from a gigakelvin plasma will definitely fry the surroundings, including the spellcasters. Since both spells last only as long as concentration is maintained, the result will be the almost instantaneous vaporization of the casters, followed immediately by the failure of the Wall of Force *and* the Enlarge spells and a (small-ish) blast due to the expanding and cooling hot plasma, which only has as much mass as the original pile of rocks -- though it is very, very hot.
So it's an amusing way of creating a (suicide) bomb, but not one with any meaningful amount of fusion.
This is some great and important work. On the second hypothesis, there’s only one problem as I see it. The way I’ve always played Wall of Force is that spells can’t be cast across it. I.e. they block spell casting. So the stone is never enlarged.
This is really quite delightful, and I feel like a terrible killjoy for pointing out that your magical nuclear fusion analysis has several problems....
The first is that you haven't really looked at how to heat the rock to T_C. You've calculated the required density needed to get your estimated Coulomb Pressure, assuming the temperature is (somehow) T_C. So how do we go from room-temperature rock to a 3 GK plasma? Rapidly forcing all that rock into a smaller volume *will* heat it up, of course, and maybe you could approximate that as an adiabatic process? (I think the problem might actually be that you pass T_C long before you reach your estimated critical density.)
The second is that silicon burning is *not* actually the fusion of two Si nuclei, so the Coulomb Pressure and critical density calculations are irrelevant. Silicon burning is a complex set of reactions based around the photodissociation of Si (and other) nuclei by gamma rays and subsequent reactions involving the interactions of the protons, neutrons, and alpha particles liberated by the Si (etc.) photodissociation.
(As it happens, the density of a stellar core undergoing silicon burning is more like 10^8 g/cm^3, so you've probably significantly overestimated the number of Enlarge spells needed.)
The third problem is that the plasma will rapidly cool down due to all the photons leaking out through the force wall (it's invisible, after all!), so I suspect that if you *do* get nuclear-burning reactions started, they won't last very long.
And in fact they really won't last very long, because the final problem is that the leakage of thermal photons from a gigakelvin plasma will definitely fry the surroundings, including the spellcasters. Since both spells last only as long as concentration is maintained, the result will be the almost instantaneous vaporization of the casters, followed immediately by the failure of the Wall of Force *and* the Enlarge spells and a (small-ish) blast due to the expanding and cooling hot plasma, which only has as much mass as the original pile of rocks -- though it is very, very hot.
So it's an amusing way of creating a (suicide) bomb, but not one with any meaningful amount of fusion.
This is some great and important work. On the second hypothesis, there’s only one problem as I see it. The way I’ve always played Wall of Force is that spells can’t be cast across it. I.e. they block spell casting. So the stone is never enlarged.