Slashdot Mirror

Here is the article that ticked me off : http://www.jp-petit.org/scienc...
Which is a reply to : http://www2.iap.fr/users/riazu...
All these conversations are in French.

Here, a cosmologist named Alain Riazuelo criticized J.P. Petit work regarding his theories. He points several mathematical mistakes. J.P. Petit answers by requesting a public confrontation, which, for some reason, doesn't get. He then goes on by saying how cowardly Alain Riazuelo, that he didn't understand anything about his theory, blah blah blah... But nowhere I see him address the technical points raised by his opponent. And no, I don't buy his excuse that he absolutely needs a seminar to defend his position.

Here's the project conference poster. "Total equipment cost for the development path is less than $1 billion". Nothing on the poster, though, indicates why this should work. It's yet another torus-based design, of which there have been many. The best performance to date is from the Joint European Torus: "In 1997, JET produced a peak of 16.1MW of fusion power (65% of input power), with fusion power of over 10MW sustained for over 0.5 sec."

All torus designs run into plasma instability problems. So far, nobody has a working solution. Nobody even has a good theoretical solution. No combination of fixed magnets has yet worked. There's some modest interest in active feedback for stabilization, and some modest success has been reported. The instabilities are on the order of milliseconds, so active feedback is quite feasible.

Even ITER probably won't work. The thinking behind ITER was originally "maybe it will become more stable if we make it bigger." Now, a little "maybe the feedback control people can make it work" has been added. It's not looking good, which is why there really isn't that much enthusiasm for ITER.

Actually, the problem with the ITER approach is that it cannot ever produce net power because of Bremsstrahlung losses inherent to its design. Simply put, you cannot heat the plasma with radiowaves AND extract useful heat from it because it's more efficient at cooling down itself radiatively in radiowaves you cannot make good use of.

That's why it's going to use Neutral Beam Heating

It is also highly vulnerable to disruptions, as are all magnetically-confined fusing plasma (all variants of tokamaks) - disruptions that are similar in nature to solar eruptions and will cause catastrophic damage.

Not all magnetic confinement devices have disruptions. Stellarator

But ITER will still eat billions, mostly in tax money, to get some science done at least... though it seems from TFA that this last part will be abandoned for the sake of trying futilely to produce energy instead.

Achieving ignition is still doing science. It's just going to be different science.

Actually, the problem with the ITER approach is that it cannot ever produce net power because of Bremsstrahlung losses inherent to its design. Simply put, you cannot heat the plasma with radiowaves AND extract useful heat from it because it's more efficient at cooling down itself radiatively in radiowaves you cannot make good use of.

It is also highly vulnerable to disruptions, as are all magnetically-confined fusing plasma (all variants of tokamaks) - disruptions that are similar in nature to solar eruptions and will cause catastrophic damage.

But ITER will still eat billions, mostly in tax money, to get some science done at least... though it seems from TFA that this last part will be abandoned for the sake of trying futilely to produce energy instead.

See by example http://arxiv.org/abs/math-ph/0502042 (http://www.jp-petit.org/science/f300/a301.htm)

Jean-Pierre Petit, ex director of CNRS, made a lot of mathematical proof of the possibility of negative mass and the implication. If interested, please read those explanations.
http://www.jp-petit.org/science/arxiv/publications_recentes.htm
Link to :
Bigravity as an interpretation of cosmic acceleration : http://www.jp-petit.org/science/arxiv/CITV_1_acceleration_english.pdf
Bigravity : A bimetric model of the Universe. Exact nonlinear solutions. Positive and negative gravitational lensings: http://www.jp-petit.org/science/arxiv/CITV_2_exact_solutions_english.pdf

Jean-Pierre Petit, ex director of CNRS, made a lot of mathematical proof of the possibility of negative mass and the implication. If interested, please read those explanations.
http://www.jp-petit.org/science/arxiv/publications_recentes.htm
Link to :
Bigravity as an interpretation of cosmic acceleration : http://www.jp-petit.org/science/arxiv/CITV_1_acceleration_english.pdf
Bigravity : A bimetric model of the Universe. Exact nonlinear solutions. Positive and negative gravitational lensings: http://www.jp-petit.org/science/arxiv/CITV_2_exact_solutions_english.pdf

Jean-Pierre Petit, ex director of CNRS, made a lot of mathematical proof of the possibility of negative mass and the implication. If interested, please read those explanations.
http://www.jp-petit.org/science/arxiv/publications_recentes.htm
Link to :
Bigravity as an interpretation of cosmic acceleration : http://www.jp-petit.org/science/arxiv/CITV_1_acceleration_english.pdf
Bigravity : A bimetric model of the Universe. Exact nonlinear solutions. Positive and negative gravitational lensings: http://www.jp-petit.org/science/arxiv/CITV_2_exact_solutions_english.pdf