plasma pressure

[choff]

I recall reading on one of rnebel's posts that the plasma pressure in a fusor was 64500 times higher on the surface than inside a tokamak, and that it got higher as it went in. Also that this made themalization irrelevant.

I'm curious how much plasma pressure by itself would be required for fusion apart from temperature or electric charge, and if anyone disagrees with the quoted number being obtainable.

If the fusor does indeed produce such high pressure how difficult is it for bremstrallung radiation to escape the core. My speculation is that fusion products would be just about the only thing energetic enough that could get out.

[TallDave]

Actually, iirc it was 250 times the ion density, 62500 times the power.

I'm curious how much plasma pressure by itself would be required for fusion apart from temperature or electric charge,

Not applicable, really, at least in my understanding. The density just increases the number of collisions, but if they're all low-energy collisions you don't get any fusion no matter how many there are. Here's the wiki brief:

The reaction cross section σ is a measure of the probability of a fusion reaction as a function of the relative velocity of the two reactant nuclei. If the reactants have a distribution of velocities, e.g. a thermal distribution with thermonuclear fusion, then it is useful to perform an average over the distributions of the product of cross section and velocity. The reaction rate (fusions per volume per time) is <σv> times the product of the reactant number densities:

If a species of nuclei is reacting with itself, such as the DD reaction, then the product n1n2 must be replaced by (1 / 2)n2.

increases from virtually zero at room temperatures up to meaningful magnitudes at temperatures of 10 – 100 keV. At these temperatures, well above typical ionization energies (13.6 eV in the hydrogen case), the fusion reactants exist in a plasma state.

The significance of <σv> as a function of temperature in a device with a particular energy confinement time is found by considering the Lawson criterion.

http://en.wikipedia.org/wiki/Nuclear_fu ... quirements

[Art Carlson]

If the fusor does indeed produce such high pressure how difficult is it for bremstrallung radiation to escape the core. My speculation is that fusion products would be just about the only thing energetic enough that could get out.

The mean free path for Bremsstrahlung radiation in any magnetic fusion device is astronomical. It is conceivable that inertial confinement devices (pellet fusion) could make a plasma dense enough to contain Bremsstrahlung, but it would be much more difficult than simply attaining fusion breakeven conditions, and even that seems to be currently impossible.