Clarifications on the Z-machine

Clarifications about the Z-machine

Clarifications

June 20, 2006.

**Last update: July 14, 2006 (at the bottom) **

June 21, 2006: Post on the Agoravox forum, June 19 edition. Title:

"2 billion degrees. Humanity discovers absolute fire and everyone couldn't care less." 128 reactions

After having taken a look at the Agoravox forum, I realized that although some people seemed to have understood the importance of the breakthrough achieved in May 2005 at Sandia on the Z-machine, others still had a rather confused idea of the whole thing, probably because I hadn't explained myself well enough. I will therefore answer the questions that emerged from this forum, or the erroneous remarks. In no particular order, from memory:

Reader's comment

: These two billion degrees are nothing special. Much more is achieved in particle accelerators.

Answer

: It's completely different. Indeed, particles can be accelerated and made to collide with a certain speed (relative V). These particles having a mass m, one can "deduce the equivalent temperature". A reader tells me that in particle accelerators, they can cause the collision of 200 nuclei. Can this population be considered as a "gas"? It's debatable. But in any case, it remains ultra-rarefied compared to a plasma, especially a dense plasma like the one created in the Z-machine.

In general, one cannot deduce conclusions applicable to the hyper-dense plasmas of "inertial fusion" from reasoning that take place in "high-energy physics", related to hyper-rarefied media.

I notice that some readers still don't understand the idea of "inertial confinement". The atoms are pressed against each other "for a certain time". If the conditions are such that the mean free path of reaction (here, fusion) is small compared to the time during which this medium remains confined, then the reaction (fusion) occurs.

A hydrogen bomb works with inertial confinement. Lithium deuteride is compressed and remains "confined" for a sufficient time for fusion reactions to occur. In bombs, this is measured in tens of nanoseconds.

Reader's comment

: These two billion degrees are nothing special. Much more is achieved in particle accelerators.

Answer

: It's completely different. Indeed, particles can be accelerated and made to collide with a certain speed (relative V). These particles having a mass m, one can "deduce the equivalent temperature". A reader tells me that in particle accelerators, they can cause the collision of 200 nuclei. Can this population be considered as a "gas"? It's debatable. But in any case, it remains ultra-rarefied compared to a plasma, especially a dense plasma like the one created in the Z-machine.

In general, one cannot deduce conclusions applicable to the hyper-dense plasmas of "inertial fusion" from reasoning that take place in "high-energy physics", related to hyper-rarefied media.

I notice that some readers still don't understand the idea of "inertial confinement". The atoms are pressed against each other "for a certain time". If the conditions are such that the mean free path of reaction (here, fusion) is small compared to the time during which this medium remains confined, then the reaction (fusion) occurs.

A hydrogen bomb works with inertial confinement. Lithium deuteride is compressed and remains "confined" for a sufficient time for fusion reactions to occur. In bombs, this is measured in tens of nanoseconds.

Reader's comment

: Getting 2 billion degrees is very nice. But you still have to maintain this temperature! I remind you that this is the problem in tokamaks and machines like ITER "which still have many good days ahead".

Answer

: In "inertial fusion", the confinement is precisely due to inertia and it is of very short duration. But it is sufficient for the fusion reactions to take place. A hydrogen bomb is an inertial confinement system where lithium hydride is abruptly compressed by the radiation pressure provided by the explosion of an A-bomb (in the form of X-rays). Simpler, an A-bomb works by inertial confinement. A hollow sphere of plutonium is abruptly compressed using an explosive. And everything happens in tens of nanoseconds. And it works with "only" 500 million degrees. If you placed a lithium hydride needle on the axis of the "wire array" of the Z-machine, with 2 billion degrees, I think the fusion would be instant. I think the Americans rushed to do the experiment, but they didn't shout it from the rooftops, given the "defense" implications. This would also explain the decision of the US Congress to replace the 6000 American warheads with "new bombs".

On the contrary, at the core of the Sun, where there are only 20 million degrees, "fusion takes its time".

The famous "Lawson criterion" is simply obtained by expressing that during the time the temperature is reached, the fusion reactions have time to take place. It's a question of "collision cross sections". In a tokamak like ITER, fusion is obviously slow (otherwise the machine ... would explode like a bomb).

The explosion engine is a good image of an inertial confinement reaction. The combustion is very rapid and occurs during the brief temperature excursion (in a diesel, at the end of compression). Thus, the comparison of ITER with ... the steam engine is not so silly as it seems. In the steam engine, calories are continuously supplied, in a boiler. In an "explosion" engine, they are supplied by impulses, during very short periods.

Reader's comment

: Getting 2 billion degrees is very nice. But you still have to maintain this temperature! I remind you that this is the problem in tokamaks and machines like ITER "which still have many good days ahead".

Answer

: In "inertial fusion", the confinement is precisely due to inertia and it is of very short duration. But it is sufficient for the fusion reactions to take place. A hydrogen bomb is an inertial confinement system where lithium hydride is abruptly compressed by the radiation pressure provided by the explosion of an A-bomb (in the form of X-rays). Simpler, an A-bomb works by inertial confinement. A hollow sphere of plutonium is abruptly compressed using an explosive. And everything happens in tens of nanoseconds. And it works with "only" 500 million degrees. If you placed a lithium hydride needle on the axis of the "wire array" of the Z-machine, with 2 billion degrees, I think the fusion would be instant. I think the Americans rushed to do the experiment, but they didn't shout it from the rooftops, given the "defense" implications. This would also explain the decision of the US Congress to replace the 6000 American warheads with "new bombs".

On the contrary, at the core of the Sun, where there are only 20 million degrees, "fusion takes its time".

The famous "Lawson criterion" is simply obtained by expressing that during the time the temperature is reached, the fusion reactions have time to take place. It's a question of "collision cross sections". In a tokamak like ITER, fusion is obviously slow (otherwise the machine ... would explode like a bomb).

The explosion engine is a good image of an inertial confinement reaction. The combustion is very rapid and occurs during the brief temperature excursion (in a diesel, at the end of compression). Thus, the comparison of ITER with ... the steam engine is not so silly as it seems. In the steam engine, calories are continuously supplied, in a boiler. In an "explosion" engine, they are supplied by impulses, during very short periods.

Reader's comment

: I don't see how one could turn a Z-machine into an electricity generator. You have to put everything back in place each time, right?

Answer

: The first cannons were not loaded from the mouth. You had to put in the powder, the wadding, the shot. It was ... slow. In a machine gun or a rapid-fire cannon, it's ... much faster, because in the meantime, they invented the cartridge. Imagine "cartridges" made up of disk-shaped electrode assemblies, a wire array (the "cage for the serin") and a lithium hydride target (armed, it's a soft metal) arranged along the axis. Imagine replacing these cartridges in the machine at a fast rate.

The idea is from a non-scientific reader!

Reader's comment

: I don't see how one could turn a Z-machine into an electricity generator. You have to put everything back in place each time, right?

Answer

: The first cannons were not loaded from the mouth. You had to put in the powder, the wadding, the shot. It was ... slow. In a machine gun or a rapid-fire cannon, it's ... much faster, because in the meantime, they invented the cartridge. Imagine "cartridges" made up of disk-shaped electrode assemblies, a wire array (the "cage for the serin") and a lithium hydride target (armed, it's a soft metal) arranged along the axis. Imagine replacing these cartridges in the machine at a fast rate.

The idea is from a non-scientific reader!

| Reader's comment | : I don't see how one could

Reader's comment

: I don't see how one could turn a Z-machine into a bomb. It's heavy and cumbersome.

Answer

: Reread my files. The Z-machine delivers 20 million amps in a fraction of a microsecond (0.1 µs). But the Russian disk generator delivers 35 million amps in a fraction of a microsecond and it's an explosive device, weighing about a hundred kilograms. On my site, the reader will find all the "meccano" pieces to make a lithium hydride bomb with "pure fusion" by linking magnetopyrotechnical systems (Russian style). If this fusion was achieved at Sandia (and I am convinced that it was), then it is on these systems that the teams from Los Alamos and Livermore (see article in the Los Angeles Times) have been working day and night for a year.

Reader's comment

: One should wait for this result, these two billion degrees, to be confirmed by other teams

Answer

: For now, this impulse electrical generator, because the Sandia machine is above all that, delivers 20 million amps in 0.1 µs. It is the only one that can do that. The military research center in Gramat (France, Lot) generator delivers 2.5 million amps, also in sub-microsecond regime. The English generator Magpie delivers 1.4 million amps. The Russians may not have an equivalent of the Z-machine yet, but it won't take long.

So far, people had not felt it necessary to aim for higher amperages, because these machines were designed as X-ray sources with temperatures at the end of compression of a few million degrees (2 million degrees at Sandia a few years ago, in 1999, I think).

This being said, a machine like the Sandia Z-Machine costs 100 million dollars, a hundredth of ITER (10 billion dollars and probably more at the end). Logically, it should be set up immediately. Bavay, in his thesis (see on my site), had recommended 60 million amps in 100 nanoseconds. The French have the expertise to build this in less than a year. Believe me, "other teams are being set up," but most likely under the cover of national defense. As for the Z-machine, it will soon have a big sister, the ZR, with 27 million amps.

Finally, the abundance of measurement tools at Sandia, the seriousness of the team, the competence of people like Malcom Haines, etc., make the artifact not feasible. Deeney has said: we have repeated the experiment N times to be sure we weren't dreaming!

Why such a sudden jump in temperature, a jump of a thousandfold in less than 5 years? Because in the Z-machine, we do not compress a plasma (gaseous, subject to many MHD instabilities), but we launch stainless steel rods against each other. The metal (Bavay's thesis) sublimes relatively slowly, "the core remaining cold". They are currently looking for the sublimation rate of stainless steel. If it is slower than that of tungsten, this would explain the jump: the system would remain in the form of metal rods, dense, for longer, therefore the confinement could be greater than with tungsten.

Reader's comment

: One should wait for this result, these two billion degrees, to be confirmed by other teams

Answer

: For now, this impulse electrical generator, because the Sandia machine is above all that, delivers 20 million amps in 0.1 µs. It is the only one that can do that. The military research center in Gramat (France, Lot) generator delivers 2.5 million amps, also in sub-microsecond regime. The English generator Magpie delivers 1.4 million amps. The Russians may not have an equivalent of the Z-machine yet, but it won't take long.

So far, people had not felt it necessary to aim for higher amperages, because these machines were designed as X-ray sources with temperatures at the end of compression of a few million degrees (2 million degrees at Sandia a few years ago, in 1999, I think).

This being said, a machine like the Sandia Z-Machine costs 100 million dollars, a hundredth of ITER (10 billion dollars and probably more at the end). Logically, it should be set up immediately. Bavay, in his thesis (see on my site), had recommended 60 million amps in 100 nanoseconds. The French have the expertise to build this in less than a year. Believe me, "other teams are being set up," but most likely under the cover of national defense. As for the Z-machine, it will soon have a big sister, the ZR, with 27 million amps.

Finally, the abundance of measurement tools at Sandia, the seriousness of the team, the competence of people like Malcom Haines, etc., make the artifact not feasible. Deeney has said: we have repeated the experiment N times to be sure we weren't dreaming!

Why such a sudden jump in temperature, a jump of a thousandfold in less than 5 years? Because in the Z-machine, we do not compress a plasma (gaseous, subject to many MHD instabilities), but we launch stainless steel rods against each other. The metal (Bavay's thesis) sublimes relatively slowly, "the core remaining cold". They are currently looking for the sublimation rate of stainless steel. If it is slower than that of tungsten, this would explain the jump: the system would remain in the form of metal rods, dense, for longer, therefore the confinement could be greater than with tungsten.

Reader's comment

: Let's stay calm. There is always a long time between a discovery and its applications. Look at fusion. We have been struggling for half a century. All of this is too recent, we need to wait, avoid "misinforming".

Answer

: Counterexample: between the first beginnings of fission, in 1938 and Hiroshima: 7 small years. For "large-scale applications," it was rather quick. And, before the bomb, the first reactor, designed by Fermi, diverged well before. People tend to forget this.

Reader's comment

: Let's stay calm. There is always a long time between a discovery and its applications. Look at fusion. We have been struggling for half a century. All of this is too recent, we need to wait, avoid "misinforming".

Answer

: Counterexample: between the first beginnings of fission, in 1938 and Hiroshima: 7 small years. For "large-scale applications," it was rather quick. And, before the bomb, the first reactor, designed by Fermi, diverged well before. People tend to forget this.

Reader's comment

: How to store energy in a fusion electrical generator?

Answer

: Within a few days, people have already considered a lot of solutions, formulas. The idea would obviously not be to try to turn the Z-machine into a generator as it is. The conversion of the fusion energy, carried by helium nuclei launched at high speed (but not neutrons!) does not pose

any problem

. We couple it to an MHD induction generator, a simple solenoid in which the expansion of the plasma creates an induced current, with a 90% efficiency. One cannot dream of something simpler.

The recharging of the chamber does not pose any problem either. The storage of energy remains. It's engineering. There are a thousand possible solutions and in a generator, one does not have the constraints of weight and bulk. For information, a mechanical storage is feasible, with a multi-rotor system.

Another detail: the tokamaks where the magnetic field is created impulsively use a rotor where the energy has been stored in kinetic form. By coupling to the solenoid of the machine, this "electric motor" is practically short-circuited and it manages to deliver a million amps. In the old tokamaks like that of Fontenay-aux-Roses, the short-lived magnetic field was created by ... a mountain of capacitors. Capacitors give abrupt discharges but contain few Joules, little energy. I don't know if with the Joules of the Z-machine we would be able to ... cook a chicken.

Reader's comment

: How to store energy in a fusion electrical generator?

Answer

: Within a few days, people have already considered a lot of solutions, formulas. The idea would obviously not be to try to turn the Z-machine into a generator as it is. The conversion of the fusion energy, carried by helium nuclei launched at high speed (but not neutrons!) does not pose

any problem

. We couple it to an MHD induction generator, a simple solenoid in which the expansion of the plasma creates an induced current, with a 90% efficiency. One cannot dream of something simpler.

The recharging of the chamber does not pose any problem either. The storage of energy remains. It's engineering. There are a thousand possible solutions and in a generator, one does not have the constraints of weight and bulk. For information, a mechanical storage is feasible, with a multi-rotor system.

Another detail: the tokamaks where the magnetic field is created impulsively use a rotor where the energy has been stored in kinetic form. By coupling to the solenoid of the machine, this "electric motor" is practically short-circuited and it manages to deliver a million amps. In the old tokamaks like that of Fontenay-aux-Roses, the short-lived magnetic field was created by ... a mountain of capacitors. Capacitors give abrupt discharges but contain few Joules, little energy. I don't know if with the Joules of the Z-machine we would be able to ... cook a chicken.

Reader's comment

: What is suspicious is that the media do not give it any echo.

Answer

: The French science media are under the control of lobbies. In a French popular science magazine, before talking about a subject, they will check whether it doesn't bother anyone. Imagine the impact of Sandia's 2 billion degrees on projects like Megajoule and Iter, which aim for hundreds of millions and will never go higher. More disturbing, meurs.

A magazine like Pour la Science is only the translation of Scientific American. The editorial staff will therefore patiently wait for the American magazine to talk about it. Other magazines wait for the American magazine to take the lead, like Science or Nature, etc.

That being said, what is astonishing is the silence of these major Anglo-Saxon science media like Scientific American, Science, Nature, three months after the event. Nothing, not even a critical word. This silence seems

highly suspicious.

Reader's comment

: What is suspicious is that the media do not give it any echo.

Answer

: The French science media are under the control of lobbies. In a French popular science magazine, before talking about a subject, they will check whether it doesn't bother anyone. Imagine the impact of Sandia's 2 billion degrees on projects like Megajoule and Iter, which aim for hundreds of millions and will never go higher. More disturbing, meurs.

A magazine like Pour la Science is only the translation of Scientific American. The editorial staff will therefore patiently wait for the American magazine to talk about it. Other magazines wait for the American magazine to take the lead, like Science or Nature, etc.

That being said, what is astonishing is the silence of these major Anglo-Saxon science media like Scientific American, Science, Nature, three months after the event. Nothing, not even a critical word. This silence seems

highly suspicious.

| Reader's comment | : This image published,

**June 21, 2006 **

Reader's reaction on the Agoravox forum

As I understand the phenomenon (I am not a specialist either, but I work in an adjacent field. My opinion is therefore comparable to that of a dentist if you ask him how bone growth works)... the idea is to use the beast as a kind of explosion engine: you make frequent shots with a superheated plasma and you ignite the thermonuclear reaction for very short periods. But the sum of the periods is supposed to do more than continuous ignition: like the explosion engine compared to a steam engine. Thus, you avoid the need to confine the plasma to burn at monstrous pressures for a very long time.

I leave you to imagine the practical difficulties that will arise when you want to industrialize the process: chaining shots every second and converting the energy thus obtained into electricity in a reliable and uninterrupted way for several years.

These practical difficulties will take some time to be resolved and other ones that we cannot foresee today will arise along the way. The scientific-industrial field is full of examples where the scientific principle is known, but the industrial implementation takes decades. The example of TOKAMAK is one...

I therefore personally think that ITER still has many good years ahead before we know more about the practical application of the Z machine.

It seems to me just as absurd to refuse to study the Z machine, as to abandon ITER, which is very close to an industrial prototype, in the name of a process whose industrial implementation is still in the realm of imagination.

My comment

These remarks evoke what could be the response of a steam engine specialist who, faced with a project for an explosion engine, would say: "You imagine the shocks that your 'generator operating on diesel' as you call it, will undergo at each cycle. This poses considerable problems. In a steam engine, the steam is introduced gradually into the cylinder. But with what you suggest, you imagine the shocks that the connecting rod would undergo! Your 'explosion engine' would simply explode, my good sir. Or else, for this new formula to bear fruit, many technical difficulties must be resolved, and it will take a long time!"

He refers to tokamaks to show that implementation can be laborious and take a long time (in this case, half a century). But perhaps it's because the formula isn't ... the right one. Well-designed things work very quickly, even if they are monstrosities. Examples: the first nuclear reactors, the A-bomb, the H-bomb, the V1, V2, the helicopter, the jet engine, the Russian powder MHD generators, the sending of men to the Moon, etc.... etc....

ITER: very close to an industrial prototype? What about the unresolved problems ... that this "non-specialist" intervenant seems to completely ignore.

His last two sentences betray the complete ignorance of this intervenant regarding French research policy. ITER and Megajoule have simply crushed any research that would have represented another path, such as the impulsive fusion experiments by electromagnetic compression. The classic argument was "we have to make choices". And all the eggs were put into these two baskets, excluding everything else. Any shadow of contestation of the French policy on the path to energy from fusion provokes an intense and immediate barrage. The reaction is even ... extremely violent.

Let's make a point. Sandia has a machine that has achieved the breakthrough with 20 million amps. The next one, ZR, will give pulses of 27 million amps. Modest progress. But these machines, let's remember, were only designed as X-ray generators. France has a machine in Gramat that reaches 2.5 million amps. Very clever, better designed than the American machine, cheaper. At Sandia, they still immerse everything in water acting as a dielectric. A formula that dates back more than 30 years. See Pour la Science of January 1979.

The English have Magpie, which reaches 1.4 mega amps. Too little. The project of a generator developing 60 mega amps in 100 nanoseconds exists. The French have the expertise to build this ... immediately. Imagine that the designs already exist ... Cost: 100 million euros, that is, a hundredth of ITER. Once the go-ahead is given, this machine would be immediately operational, ready to use. The French fully master these techniques of delivering high currents in very short times. There would be no "long development phase". It's actually relatively crude engineering. All proportions considered, compared to projects like ITER and Megajoule, it's a modest project, well within the reach of France and many other countries in the world. A project with 60 million amps was what people like Bavay (PhD, Supélec) and the designer of the machine on which he did his tests had come up with. Bavay had even brought his double wire array compressor to Sandia to benefit from the current source of the ... Z-machine, at Sandia. Read in his thesis the results of the tests in question. It was therefore not a complete stranger across the Atlantic, and it was in the United States that this brilliant researcher went after his thesis, to ... Sandia.

One more...

What will happen? Let's wait. Anyway, given the stakes and the relatively modest cost, the reaction should be quick. Will it be?

Reader's reaction on the Agoravox forum

"

As I understand the phenomenon (I am not a specialist either, but I work in an adjacent field. My opinion is therefore comparable to that of a dentist if you ask him how bone growth works)... the idea is to use the beast as a kind of explosion engine: you make frequent shots with a superheated plasma and you ignite the thermonuclear reaction for very short periods. But the sum of the periods is supposed to do more than continuous ignition: like the explosion engine compared to a steam engine. Thus, you avoid the need to confine the plasma to burn at monstrous pressures for a very long time.

I leave you to imagine the practical difficulties that will arise when you want to industrialize the process: chaining shots every second and converting the energy thus obtained into electricity in a reliable and uninterrupted way for several years.

These practical difficulties will take some time to be resolved and other ones that we cannot foresee today will arise along the way. The scientific-industrial field is full of examples where the scientific principle is known, but the industrial implementation takes decades. The example of TOKAMAK is one...

I therefore personally think that ITER still has many good years ahead before we know more about the practical application of the Z machine.

It seems to me just as absurd to refuse to study the Z machine, as to abandon ITER, which is very close to an industrial prototype, in the name of a process whose industrial implementation is still in the realm of imagination.

. "

My comment

:

These statements evoke what could be the response of a steam machine specialist who, faced with an explosion engine project, would write: "You imagine the shocks that your 'diesel-powered generator' as you call it, will undergo at each cycle. This poses considerable problems. In a steam machine, it is gradually introduced into the cylinder. But with what you suggest, you imagine the shocks that the crankshaft would undergo! Your 'explosion engine' would simply explode, my dear sir. Or else, for this new formula to lead anywhere, many technical difficulties will have to be solved, and that will take a long time!"

He refers to tokamaks to show that implementation can be laborious and take a long time (in this case, half a century). But perhaps it is because the formula is not the right one. Well-designed things work very quickly, even if they are monstrosities. Examples: the first nuclear reactor, the A-bomb, the H-bomb, the V1, V2, the helicopter, the jet plane, the Russian powder MHD generators, sending men to the Moon, etc.

ITER: very close to an industrial prototype? What is being done about the unresolved problems that this "non-expert" speaker seems to totally ignore.

His last two sentences betray the complete ignorance of this speaker regarding research policy in France. ITER and Megajoule have simply crushed any research that would have represented another path, such as the impulsive fusion experiments by electromagnetic compression. The classic argument was "we have to make choices." And all the eggs were put into these two baskets, excluding everything else. Any shadow of contestation of the French policy towards the path of energy from fusion provokes an intense and immediate barrage. The reaction is even extremely violent.

Let's take stock. Sandia has a machine that has achieved a breakthrough with 20 million amperes. The next one, ZR, will give pulses of 27 million amperes. A modest progress. But these machines, let's recall, were only designed as X-ray generators. France has a machine in Gramat that reaches 2.5 million amperes. Very clever, better designed than the American machine, cheaper. At Sandia, they still immerse everything in water acting as a dielectric. A formula that is over 30 years old. See Pour la Science of January 1979.

The British have Magpie, which reaches 1.4 mega amperes. Too little. A project for a generator developing 60 mega amperes in 100 nanoseconds exists. The French have the expertise to build this... immediately. Imagine that the designs already exist... Cost: 100 million euros, that is one hundredth of ITER. With the green light, this machine would be immediately operational, ready to use. The French completely master these techniques of delivering high currents in very short times. There would be no "long development period." It is in fact relatively rough engineering. All proportions considered, compared to projects like ITER and Megajoule, it is a modest project, well within the reach of France and many other countries in the world. A project with 60 million amperes was what people like Bavay (a doctoral student, Supélec) and the designer of the machine on which he did his tests had arrived at. Bavay had even brought his double-layered wire compressor to Sandia to benefit from the current source of the... Z-machine, at Sandia. Read the results of the tests in his thesis. So he was not a complete unknown across the Atlantic and it was in the United States that this brilliant researcher went after his thesis, to... Sandia.

One more...

What will happen? Let's wait. Anyway, given the stakes and the relatively modest expense, the reaction should be quick. Will it be?

June 23, 2006

Reader's comment

I'm willing to believe that the lithium hydride targets suggested to be placed at the center of these impulsive fusion machines can fuse. But in that case, if a one-gram target is placed, it should blow up the lab every time. The shock wave produced by the explosion should damage the solenoid constituting the "MHD induction generator," right?

My answer

As was considered in laser fusion (a deuterium-tritium mixture contained in tiny glass balls), these targets would contain much smaller amounts of Li-H. Each explosion would not be more powerful than that of a large firecracker. It is the rate of repeated explosions that would allow, for example, 1000 MW of electricity. Moreover, the target is surrounded by a magnetic field, which recovers the produced energy, but instead of being the wall of a piston, it presents itself as a soft obstacle, a kind of "magnetic duvet" that will absorb the energy.

Reader's comment:

I'm willing to believe that the lithium hydride targets suggested to be placed at the center of these impulsive fusion machines can fuse. But in that case, if a one-gram target is placed, it should blow up the lab every time. The shock wave produced by the explosion should damage the solenoid constituting the "MHD induction generator," right?

My answer:

As was considered in laser fusion (a deuterium-tritium mixture contained in tiny glass balls), these targets would contain much smaller amounts of Li-H. Each explosion would not be more powerful than that of a large firecracker. It is the rate of repeated explosions that would allow, for example, 1000 MW of electricity. Moreover, the target is surrounded by a magnetic field, which recovers the produced energy, but instead of being the wall of a piston, it presents itself as a soft obstacle, a kind of "magnetic duvet" that will absorb the energy.

Noted by forum participants, two things

1 - The British are following the Americans' example by also announcing their intention to replace their nuclear warheads.

2 - Japanese Nobel Prize winner Koshiba joins de Gennes in his criticisms:

Currently, he points out, nuclear fission releases neutrons of an average energy of only one or two MeV. For M. Koshiba, scientists must first solve this problem of 14 MeV neutrons "by building walls or absorbers" before being able to claim that it is a new and sustainable energy. It is, he says, a very costly solution. "If they have to replace the absorbers every six months, it will lead to operational shutdowns that will result in an energy cost increase," criticizes the physicist. "This project is no longer in the hands of scientists, but in those of politicians and businessmen. Scientists can no longer change anything," he laments before adding: "I'm afraid." (...)

"I wish the French government had the honor of accepting Iter in its own country," sarcastically says M. Koshiba. "French scientists may know better how to handle these 14 MeV neutrons. After all, France is already actively involved in the treatment of radioactive materials in its nuclear power plants." "I think, he concludes, that certainly, French scientists and engineers have more knowledge and experience than those of other countries to tackle this new 14 MeV neutron problem," he concludes.

Noted by forum participants, two things:

1 - The British are following the Americans' example by also announcing their intention to replace their nuclear warheads.

2 - Japanese Nobel Prize winner Koshiba joins de Gennes in his criticisms:

Currently, he points out, nuclear fission releases neutrons of an average energy of only one or two MeV. For M. Koshiba, scientists must first solve this problem of 14 MeV neutrons "by building walls or absorbers" before being able to claim that it is a new and sustainable energy. It is, he says, a very costly solution. "If they have to replace the absorbers every six months, it will lead to operational shutdowns that will result in an energy cost increase," criticizes the physicist. "This project is no longer in the hands of scientists, but in those of politicians and businessmen. Scientists can no longer change anything," he laments before adding: "I'm afraid." (...)

"I wish the French government had the honor of accepting Iter in its own country," sarcastically says M. Koshiba. "French scientists may know better how to handle these 14 MeV neutrons. After all, France is already actively involved in the treatment of radioactive materials in its nuclear power plants." "I think, he concludes, that certainly, French scientists and engineers have more knowledge and experience than those of other countries to tackle this new 14 MeV neutron problem," he concludes.

Julien Geffray on June 23, 2006 at 11:03

Current news seems to give Jean-Pierre Petit the right to say that the nuclear arms race is resuming, alas.

It may or may not have anything to do with the "discovery" of the Sandia Z-machine (or perhaps it is a direct consequence, with new exclusive fusion weapons, with all possible power levels from low to unlimited...).

In any case, after the USA, it is now the British who have just announced the renewal of their entire nuclear warhead stockpile!

This nuclear arsenal "to be improved," according to the finance minister -and probable successor of Tony Blair- Gordon Brown, during a speech in London on Wednesday, June 21, 2006. The United Kingdom has four nuclear-powered Trident ballistic missile submarines, each equipped with sixteen warheads with a range of about 12,000 km. The renewal of the system, which must take place by 2024, would cost between 14.6 and 36.4 billion euros according to experts.

SOURCES

Article from the daily "20 minutes" No. 993, 23/06/06, p.13: "In London, nuclear power divides the laborers" and on the web: http://www.20minutes.fr/articl...

And in England, numerous and more detailed articles:

The Independent - "Britain to renew nuclear missiles after Brown pledges his support": http://news.independent.co.uk/uk/politics/article1094711.ece

Times - "Arms and the man": http://www.timesonline.co.uk/article/0,,542-2238940,00.html

Financial Times:

"Brown snubs left with Trident pledge": http://www.ft.com/cms/s/0e0eabd6-015b-11db-af16-0000779e2340.html

"Brown homes in on targets with Trident stance": http://www.ft.com/cms/s/f3fc8e80-018b-11db-af16-0000779e2340.html

"Brown in pledge to replace Trident": http://www.ft.com/cms/s/8aad9686-018b-11db-af16-0000779e2340.html

"Brown fires only first shot in missile debate": http://www.ft.com/cms/s/49b2c654-0255-11db-a141-0000779e2340.html

Julien Geffray on June 23, 2006 at 11:03

Current news seems to give Jean-Pierre Petit the right to say that the nuclear arms race is resuming, alas.

It may or may not have anything to do with the "discovery" of the Sandia Z-machine (or perhaps it is a direct consequence, with new exclusive fusion weapons, with all possible power levels from low to unlimited...).

In any case, after the USA, it is now the British who have just announced the renewal of their entire nuclear warhead stockpile!

This nuclear arsenal "to be improved," according to the finance minister -and probable successor of Tony Blair- Gordon Brown, during a speech in London on Wednesday, June 21, 2006. The United Kingdom has four nuclear-powered Trident ballistic missile submarines, each equipped with sixteen warheads with a range of about 12,000 km. The renewal of the system, which must take place by 2024, would cost between 14.6 and 36.4 billion euros according to experts.

SOURCES:

Article from the daily "20 minutes" No. 993, 23/06/06, p.13: "In London, nuclear power divides the laborers" and on the web: http://www.20minutes.fr/articl...

And in England, numerous and more detailed articles:

The Independent - "Britain to renew nuclear missiles after Brown pledges his support": http://news.independent.co.uk/uk/politics/article1094711.ece

Times - "Arms and the man": http://www.timesonline.co.uk/article/0,,542-2238940,00.html

Financial Times:

"Brown snubs left with Trident pledge": http://www.ft.com/cms/s/0e0eabd6-015b-11db-af16-0000779e2340.html

"Brown homes in on targets with Trident stance": http://www.ft.com/cms/s/f3fc8e80-018b-11db-af16-0000779e2340.html

"Brown in pledge to replace Trident": http://www.ft.com/cms/s/8aad9686-018b-11db-af16-0000779e2340.html

"Brown fires only first shot in missile debate": http://www.ft.com/cms/s/49b2c654-0255-11db-a141-0000779e2340.html

My analysis of Haines' article

June 25, 2006

Reader's question

This temperature, which is in the billions of degrees, has it been measured? Is it true that the energy emitted exceeds the kinetic energy corresponding to the implosion of the metal wires on the axis?

My answer

It is on my site, in

, at two levels (popularization and more detailed analysis). Yes, this temperature has been reliably measured. It actually evolves during the experiment, rising from 2.66 billion degrees to 3.7 billion. Indeed, the kinetic energy is 3 to 4 times less than the energy emitted by the machine, in the form of X-rays. Haines justifies this by saying that during the implosion, a large amount of energy is localized in the space surrounding all the wires, in the form of a magnetic field. Where there is a magnetic field, there is magnetic pressure. And pressure is an energy density per unit of volume. If you create a magnetic field in a vacuum, this vacuum starts to contain energy. He proposes an idea according to which "MHD instabilities" would allow part of this energy to heat the iron ions. But this theory is still in its infancy. Nevertheless, the fact is absolutely undeniable.

June 25, 2006

Reader's question:

This temperature, which is in the billions of degrees, has it been measured? Is it true that the energy emitted exceeds the kinetic energy corresponding to the implosion of the metal wires on the axis?

My answer:

It is on my site, in

, at two levels (popularization and more detailed analysis). Yes, this temperature has been reliably measured. It actually evolves during the experiment, rising from 2.66 billion degrees to 3.7 billion. Indeed, the kinetic energy is 3 to 4 times less than the energy emitted by the machine, in the form of X-rays. Haines justifies this by saying that during the implosion, a large amount of energy is localized in the space surrounding all the wires, in the form of a magnetic field. Where there is a magnetic field, there is magnetic pressure. And pressure is an energy density per unit of volume. If you create a magnetic field in a vacuum, this vacuum starts to contain energy. He proposes an idea according to which "MHD instabilities" would allow part of this energy to heat the iron ions. But this theory is still in its infancy. Nevertheless, the fact is absolutely undeniable.

A reader

How would the Americans adopt a nuclear bomb without testing it?

Answer

The "pure fusion" bomb, with lithium hydride, only produces helium. It is a perfectly ecological bomb. You can breathe the waste it produces without problems. It is, in a way, the "green bomb." Moreover, it is enough to validate the concept. If a lithium hydride charge the size of a matchstick can be ignited, then this primer can in turn explode an unlimited amount of thermonuclear explosive. These bombs, not producing radioactivity, do not fall within the framework of the treaties banning atmospheric tests and could be tested outdoors, or even underwater (no revealing pollution).

Kill me cleanly (kill me properly)

A reader:

How would the Americans adopt a nuclear bomb without testing it?

Answer:

The "pure fusion" bomb, with lithium hydride, only produces helium. It is a perfectly ecological bomb. You can breathe the waste it produces without problems. It is, in a way, the "green bomb." Moreover, it is enough to validate the concept. If a lithium hydride charge the size of a matchstick can be ignited, then this primer can in turn explode an unlimited amount of thermonuclear explosive. These bombs, not producing radioactivity, do not fall within the framework of the treaties banning atmospheric tests and could be tested outdoors, or even underwater (no revealing pollution).

Kill me cleanly (kill me properly)

July 14, 2006

: Why do Z-machines have to deliver their "pulse" in such a short time?

20 million amperes in 100 nanoseconds! Why aim for such a short time? Why not one or several microseconds?

What gives heat to the ion gas is not the Joule effect, since there is a certain energy decoupling between the ion gas and the electron gas, it is the kinetic energy acquired by the wires along their course when they converge toward the axis, abruptly converted into heat at the moment of impact (stagnation conduction). The current flowing through the wires is electronic and not ionic. It is therefore the electrons that undergo the Laplace force V

x

B. It is the electron gas that is projected toward the axis. The electrons thus acquire kinetic energy, which will be redistributed in all directions by electron-electron and electron-ion collisions. But iron ions and electrons have very different masses. The ratio is on the order of ten thousand. In this process of acceleration toward the axis and heating at impact, it is the ions that are the winners, which immediately creates this out-of-equilibrium, bitemperature situation, which we are not used to. From the moment of impact, the temperature in the ion gas is already much higher than that of the electron gas. Why do the ions follow the electrons when the latter, subjected to the action of the Laplace force, plunge toward the axis? Is it because of collisions? Very partially. Electrons and ions remain closely linked by the electric field and can only be separated by a distance called the Debye length, which is small.

If the implosion time is too long, because the current pulse is too spread out in time (the number of joules available in the discharge is limited), the wires will have time to sublime. Leaving their solid metallic prison, the electrons, interacting with the magnetic field, will represent an important radiative energy loss through braking radiation. If the liner material goes into a plasma state, the pressure forces will oppose the collapse earlier. The maximum efficiency will be achieved if we manage to bring the material in the form of solid wires as close as possible to the axis of the system.

The entire process remains complex. All we know is that under current conditions, with the chosen parameters, it works.

July 14, 2006

: Why do Z-machines have to deliver their "pulse" in such a short time?

20 million amperes in 100 nanoseconds! Why aim for such a short time? Why not one or several microseconds?

What gives heat to the ion gas is not the Joule effect, since there is a certain energy decoupling between the ion gas and the electron gas, it is the kinetic energy acquired by the wires along their course when they converge toward the axis, abruptly converted into heat at the moment of impact (stagnation conduction). The current flowing through the wires is electronic and not ionic. It is therefore the electrons that undergo the Laplace force V

x

B. It is the electron gas that is projected toward the axis. The electrons thus acquire kinetic energy, which will be redistributed in all directions by electron-electron and electron-ion collisions. But iron ions and electrons have very different masses. The ratio is on the order of ten thousand. In this process of acceleration toward the axis and heating at impact, it is the ions that are the winners, which immediately creates this out-of-equilibrium, bitemperature situation, which we are not used to. From the moment of impact, the temperature in the ion gas is already much higher than that of the electron gas. Why do the ions follow the electrons when the latter, subjected to the action of the Laplace force, plunge toward the axis? Is it because of collisions? Very partially. Electrons and ions remain closely linked by the electric field and can only be separated by a distance called the Debye length, which is small.

If the implosion time is too long, because the current pulse is too spread out in time (the number of joules available in the discharge is limited), the wires will have time to sublime. Leaving their solid metallic prison, the electrons, interacting with the magnetic field, will represent an important radiative energy loss through braking radiation. If the liner material goes into a plasma state, the pressure forces will oppose the collapse earlier. The maximum efficiency will be achieved if we manage to bring the material in the form of solid wires as close as possible to the axis of the system.

The entire process remains complex. All we know is that under current conditions, with the chosen parameters, it works.

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