Two Billion Kelvin ...

Kuroneko · Post by **Kuroneko** » 2006-03-09 08:37pm

Admiral Valdemar wrote:I was under the impression the Z-machine, and the original Oxford version, worked with denser plasmas than you'd see in a tokamak if only due to their sizes.

Well, personally I have no idea; hence my question as to what was the density or pressure of the plasma for this achievement.

Ariphaos · Post by **Ariphaos** » 2006-03-09 09:50pm

Admiral Valdemar wrote:I find it hard to believe that people sit in saunas where water is, literally, boiling. Do they enjoy scolding their skin or something? The usual sauna is bad enough for me, though I prefer hot tubs to saunas anyway (and there's no fucking way anyone sits in boiling water).

Saunas are not always heated by the water you're bathing in, but by heating water elsewhere past boiling to steam up the atmosphere. This can regularly exceed 100C, though I personally couldn't stand that for very long.

I was under the impression the Z-machine, and the original Oxford version, worked with denser plasmas than you'd see in a tokamak if only due to their sizes. Course, if it is really not that dense, then the plasma will be fairly useless, certainly it would cool practically instantly without input (not that sci-fi accepts this with explosive fusion reactors).

I thought the tokomak designs only had like ~80 grams covering several dozen cubic meters at ~100-200 megaKelvins?

Sonnenburg · Post by **Sonnenburg** » 2006-03-09 11:48pm

drachefly wrote:Hello, we have mysterious energy source and you can only talk about saunas?

Well it's not really the billion Kelvin heat as it is the gosh darn humitidy that gets to you.

AK_Jedi · Post by **AK_Jedi** » 2006-03-10 01:01am

Admiral Valdemar wrote:ANY oven can do that. The point is, stick your hand in 100 degree C water or air, then stick it in a couple billion degrees C heat. You won't notice much, aside from your hand being vapour with the second one. Anything above boiling point of water is excessive pain, beyond that it doesn't matter what temperature you're at.

The temperature doesn't matter so much as the heat of whatever your sticking your hand into. I can stick my hand inside my oven without feeling much pain for several moments. The same amount of time with my hand in (cooler) boiling water would result in serious pain and damage to my hand.

kheegster · Post by **kheegster** » 2006-03-10 06:56am

Kuroneko wrote:
kheegan wrote:Yes, but your hand would have suffered all the effects of what is effectively a vacuum by then.
Well, hence the qualifier 'heat damage', but even so, it's quite possible for this to be false. If the pressure and volume stay constant, increasing the temperature of a gas (thus necessarily decreasing density) does not change the internal energy of the system at all according to the ideal gas law. This is because the molar density should decrease by the exact same factor that the temperature was increased and internal energy is directly proportional to temperature.

Above a 10^5 K or so, the molecules would be fairly thoroughly ionised, so the ideal gas law would no longer hold as in the plasma. Although IIRC so long as you assume a collisionless plasma the adiabatic approximation still works.

Admiral Valdemar · Post by **Admiral Valdemar** » 2006-03-10 07:24am

AK_Jedi wrote:
The temperature doesn't matter so much as the heat of whatever your sticking your hand into. I can stick my hand inside my oven without feeling much pain for several moments. The same amount of time with my hand in (cooler) boiling water would result in serious pain and damage to my hand.

Now you're just nitpicking.

But yes, that is the reason for pondering the plasma density here and why a guy can take a sauna at 100ºC, but not a jacuzzi at the same temperature.

I'm curious about this energy output that's going on here though.

wolveraptor · Post by **wolveraptor** » 2006-03-10 08:45pm

Shouldn't this machine vaporize after each use?

kheegster · Post by **kheegster** » 2006-03-11 07:10am

wolveraptor wrote:Shouldn't this machine vaporize after each use?

To put it in a very simplistic manner, the plasma is being held away from the container walls by a system of magnetic fields, the plasma doesn't actually touch the machine.

His Divine Shadow · Post by **His Divine Shadow** » 2006-03-12 10:58am

Admiral Valdemar wrote:
AK_Jedi wrote:
The temperature doesn't matter so much as the heat of whatever your sticking your hand into. I can stick my hand inside my oven without feeling much pain for several moments. The same amount of time with my hand in (cooler) boiling water would result in serious pain and damage to my hand.
Now you're just nitpicking. But yes, that is the reason for pondering the plasma density here and why a guy can take a sauna at 100ºC, but not a jacuzzi at the same temperature.

I'm curious about this energy output that's going on here though.

Any chance there could be fusion?