nuclear fusion

Here I show the article, printed in Russian magazine "Science and life" 1 in the 2000 year. The author offered use of accelerators of the charged particles on counter beams for getting of the economically favourable reaction of controlled nuclear synthesis. He give of the mathematical calculations of physical processes and an economic substantiation of this project. The author of the article assert that financial expenses for creation of similar installation will be in 10 - 20 thousand times less than on manufacturing of the TOKAMAK's or of the installation of laser synthesis. However and this installation will not suitable to transportation.
In this case the this article is interesting for us, because, if we recognize an opportunity of the decision of a problem of controlled nuclear synthesis with the help of accelerators on counter beams, then we shall be compelled with a high probability to recognize and an opportunity of getting of the CNS with the help of the phenomenon of sonoluminescence. Because during a process of collapse of the cavitational cavities, as a matter of fact, too there is an acceleration of substance. I.e. at cavitation we receive the accelerator on counter beams and therefore all convincing mathematical calculations submitted by the author of given article, will quite suitable for the description of processes of the cavitation. However, how I have already told, the installation described by the author of given article, with use of bulky accelerators on counter beams, will not be enough compact and she will not suitable to transportation.
Therefore I can make good council to the reader: not to waste too much the time for reading of this article, and at once to familiarize with my work.


Hypotheses, offers, facts

Energy from particle accelerator


The human civilization can not exist, and furthermore develop without energy. Today her basic sources it is the petroleum, gas and coal. The specialists appreciate of reserves of these minerals as very little, and already our grandsons can face with very serious problem of shortage of energy. Therefore researchers of the all developed countries cherish hopes to overcome the future energy crisis by means of the controlled thermonuclear reaction. Such reaction - synthesis of helium from deuterium and tritium - already millions years exists on the Sun, but in terrestrial conditions of her already fifty years try to carry out in huge and very expensive laser installations, tokamak's and stellarator's. However there are also other ways of the decision of this uneasy task, and instead of huge tokamak's for realization of thermonuclear synthesis, probably, it will be possible to use rather compact and inexpensive collider - the accelerator on counter beams.

Candidate of technical sciences L. Zilyakov, Institute of heats of the Russian Academy of Science.

Problem of controlled thermonuclear synthesis - one of the major tasks, which be very important for mankind. According to the World power advice, the reconnoitered reserves of hydrocarbonic fuel on the Earth remained on 50 - 80 years. The sole long-term energy source is a nuclear energy, which be result or as division, or as synthesis of the atomic nucleus. While operation of the atomic power stations working on division of nucleus of uranium, results in serious environmental problems.


The ring hall of the accelerator U - 70 (Protvino). The channel of the input of ions (in this case - protons, ions of hydrogen H) of an initial source (synchrotron) in the accelerator adjoins on the right. The accelerator - collider for thermonuclear synthesis can have much the smaller sizes.

Process of thermonuclear synthesis is substantially free from the lacks inherent in process of division. In reaction of synthesis not will form long-living radioactive isotopes, as fuel for her be used the heavy isotopes of hydrogen - deuterium and tritium. In litre of usual water contains approximately 0.03 gram of the deuterium, but during his reaction of nuclear synthesis will be as much energy, how many at combustion of 300 litres of gasoline! The reserves of the deuterium on the Earth will suffice to supply mankind with energy about billion years. And that very important, manufacture of thermonuclear fuel already today is very inexpensive: in present conditions the price would make 1 - 2 kopecks for watt of the electric power and further she else will be reduced.
Summarizing aforesaid, it is possible to draw a conclusion: who will receive controlled reaction of synthesis -



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practically completely will supply itself with energy. And we may boldly assert, that the decision of this problem will compensate all expenses. From the physical point of view the task is formulated simply. For realization of the self-sustaining reactions of nuclear synthesis enough and necessary to fulfill a two conditions.
1. Energy of nucleus, which participating in reaction, should be no less than 12 keV. For what there was a nuclear synthesis, the nucleus, which participate in reaction, of should get in a field of nuclear forces, which have radius of action 10-12 - 10-13 centimeters. However the any atomic nucleus have a positive electric charge, because we must take into account, what the like charges make repulsive interaction. On a boundary of action of nuclear forces energy of the coulomb pushing away have value about 10 keV. To overcome this barrier, nucleus at collision should have kinetic energy at least not less than given value.
2. The mathematical product of concentration of reacting nucleus on the time when they have proximity and keep the specified energy, should be not less than 1014 s
sm-3. This condition - so-called Lawson criterion - he determines a limit of the energy advantage of reaction. So as the energy, which arises in reaction of synthesis, at least defray expenses of energy on initiation of reaction, the atomic nuclei should undergo many collisions. In each collision at which there is a reaction of synthesis between deuterium (D) and tritium (T), will liberationes 17,6 MeV energy, i.e. approximately 310-12 joule. If, for example, for an arson of reaction we uses of energy 10 megajoule, then the reaction will be profitable if in her be participated not less than 3
1018 pairs D - T. But for this purpose rather dense plasma of high energy needs to be kept in a reactor long enough. Such condition and be expressed in the criterion Lowson.
If simultaneously it will be possible to execute both requirements, then the problem of controlled thermonuclear synthesis will be solved.
Schematically thermonuclear reactor can be presented as some "black box", in which we bring in the fuel (deuterium and tritium) and of the energy E1 for his heating. From "box" come out products of reaction - the alpha-particles, neutrons and energy E2, which getting at synthesis, and he should be more than E1, which we earlier spend in reactor.
However technical realization of the given physical problem meets with huge difficulties. Because the energy 10 keV - is a temperature of 100 million degrees. To keep of the such substance, which have of the such big temperature, during even a share of second, we can only in vacuum, having isolated him from walls of installation. Now the decision of a problem of controlled synthesis develops in two mainstreams: magnetic keeping of plasma (tokamak, stellarator and so forth) and inertial keeping (laser synthesis).

Thermonuclear synthesis

Thermonuclear synthesis in a beam of the laser demands a construction of the cyclopean devices. In a image - one of 192 lines of the research installation constructed in Lawrence Livermore National Laboratory (USA).


The laser synthesis by a method of the thermonuclear microexplosions, set fire by powerful laser pulses, lately develops most intensively (see. "A science and life" 11, 1999). Here already achieved big successes in technic of beams convergence, in injecting of the fuel capsules, in diagnostics of plasma etc. now here is required only one thing - the laser system, having necessary parameters and with energy of a impulse 1-10 megajoule. But today of such laser system does not exist, and, hence, in present moment there are no real reasons to predict success of the given works.
Magnetic keeping is the attempt to receive quasi-steady burning of plasma. These methods have of a history already almost in the half century. By numerous experimental researches was found, what the optimum parameters have the tokamaks - the installations in which the working chamber has the form of the torus. Just on tokamaks the researchers can very approach to required parameters of thermonuclear plasma. But on this occasion it is necessary to note small feature. Practically all success is provided due to increase of their sizes. The fact is that the theory of the tokamaks says: time of keeping of plasma is the directly proportional from the intensity of a magnetic field and a square of the size of installation. As the limit of intensity of a magnetic field is practically achieved, there is only one way - the increase of the sizes. During existence of the tokamaks their diameter has grown with 2 up to 20 meters. The tokamak with auxiliaries it is whole enterprise by cost of hundred millions and even billions dollars. Construction of the next tokamak occupies some years, and after researchers make on him of the series of experiments, they come to a conclusion: is required of the installation with the big sizes. At present time put into practice the international project "ITER", by cost more than 10 billion dollars. However there are strong doubts in that,



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what this giant construction can give a positive exit of energy (see "the Science and life" 12, 1999).
We come to very important conclusion in works with the controlled thermonuclear synthesis. Today any project, irrespective of an offered way of keeping of plasma, is estimated in billions dollars. The installations of the small sizes and smaller cost already for a long time have exhausted all potentialities. Today almost 100 thousand people all over the world work in the problem of nuclear synthesis, in search of the decision are engaged the largest scientists, skilled engineers and designers. There are absolutely no reasons to speak that in process the decision was made some an errors. And as a result of long-term researches all this army of scientists comes to a sole conclusion: the decision of a problem of controlled synthesis is possible only by increase of the sizes of installations and astronomical expenses for their construction.
Here possible make rather curious example of quite real project of the decision of a task. Are offered use of the huge steel boiler, with volume in some cubic kilometers, he on half be filled by the water, which heat explosions of thermonuclear bombs. The author not have of boldness to estimate expediency and ecological consequences of realization of the similar project. Simply given example evidently enough shows scales of searches of alternative ways of use of thermonuclear energy.
Today prospects of the controlled thermonuclear synthesis are rather contradictory. On the one hand, he practically has no equipollent alternative, on

the decision of a problem are already spent huge means and to recede one cannot. On the other hand - each new step here is given by increasingly more expenses. Many countries had to refuse continuation of researches in view of their extreme expensiveness. Even the hottest optimists expect, that the task can be solved only to middle of the next century. But by then on the Earth almost all reserves of petroleum and gas will be burnt and, hence, the mankind expects the fierce raw crisis. But if the decision nevertheless will not be found?..
But really whether prospects is so gloomy and the mankind to avoid them, it is necessary to go on fabulous expenses. Perhaps exists cheaper and accessible decision?
Such way exists. And the nature already repeatedly showed he. Already at the beginning of thermonuclear researches was found out the so-called "a pinch effect" - compression of a plasma channel by a magnetic field of a electric current. The effect provoked the emission of neutrons, which is an attribute of reaction of synthesis. At that time there were many delights, was expected the fast decision of a problem of synthesis. Very emotionally this moment was represented in known film of that time of "Nine days of one year". But all delights quickly was replacing on the disappointment: the researchers found out, that a source of neutron emission was not reaction in all volume of a channel of plasma, but only in small groups fast deuterons (deuterium nucleus). At acceleration by the electric fields arising in plasma at strong instability, deuterons received the energy, essentially



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exceeding energy of other particles of plasma, and they entered reaction of synthesis with emission of neutrons. Such "detachment from collective" the physicists very much dislike, the received neutrons were named "false", and have refused this direction of searches. But the reaction of synthesis after all was!
Another the example from the recent past. Many well remember the sensational message about "the cold nuclear synthesis". However scientists sufficiently quickly ascertain, what the effect, which discover the M. Fleischmann and S. Pons and irrespective of them S. Jones, is very weak and can not be used for receiving of energy (see "the Science and life" 6, 1989 and 3, 1990). The most probable explanation of the found out effect - so-called "accelerative model": reaction of synthesis occurs as a result of acceleration deuterons with help the strong electric field, which is arising at bursting of a palladium. Again the accelerated deuterons!
We can recollect of the history of physics. How in 1919 year E. Rezerford can receives of the first reaction of nuclear synthesis? By bombardment of nucleus of nitrogen by fast alpha - particles. How receive nucleus transuranium elements? Bombardment of nucleus of known elements by the accelerated particles. The way of realization of nuclear reactions on accelerators is absolutely natural and already nobody can have doubts in he. The level of the energy of the accelerated protons is measured already by hundreds gigaelectron-volt. For such technique the reaction of synthesis deuteron - tritium or deuteron - deuteron with energy Coulomb barrier in 10 keV does not represent of any complexity.

Nevertheless the opportunity of realization of reaction of nuclear synthesis by use of collisions of the accelerated nucleus of deuteron and tritium till now was not investigated. And for this was rather essential reasons.
The fact is that a principal objective of thermonuclear researches - getting of intensive reaction with distribution of a plenty of energy, but in accelerators nuclear reactions occur practically by the apiece. Here main not quantity of the cases of reaction, but yourself the fact of her realization. Small intensity of nuclear reactions in accelerators is defined by the quantity of particles in the speeded up beams, but them be rather few and accordingly their concentration is small. Certainly, direct use of modern accelerating technique for the decision of a problem of controlled synthesis is meaningless. For her the task of increase of concentration of particles in a beam also is relevant, but not be as the basic; here the main task - to reach the maximal energy of particles. But if we will try formulating a task a little differently? To plan and create the accelerator on counter beams with energy of the speeded up ions of the deuterons and tritium's in a few hundreds kiloelectronvolt, when reaction of synthesis already for certain will go, and with density of particles in a beam 1014 sm-3 when her intensity will be great enough for practical use. At modern development of a science and technology such task can be enough quickly solved on the accelerator of the small sizes. As show the calculations, for getting of required density of ions the size of a current in the accelerator should be in a few tens of the amperes.



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The installation for nuclear fusion in the collider

Existing today high-density accelerators of ions allow to receive currents up to 106 ampere with energy of ions up to 106 electronvolt. There is a task of beams confinement with such parameters. But and this task has the decision. In modern accelerators on counter beams the time of keeping is measured by hours! Possible also will make an attempt to construct a reactor in which collisions of beams will have pulse-periodic character. Collision of beams will have in this case the duration about 10-7 - 10-8 per seconds and "keep" them is required only during this the time. Collisions can repeat with frequency 107-108 hertz, that will mean practically continuous burning reaction.
The important difference of a method of counter beams from magnetic keeping, that the size of the accelerator does not play a basic role for achievement of conditions of synthesis. The minimal size of experimental installation will be defined only by the sizes of a source of ions with required energy. But they is modest: the source of ions in some hundreds kiloelectronvolts, used in the industry (for example, for ion implantation in the semiconductors),

The scheme of installation for thermonuclear synthesis in the collider. The collider represents a pair of the accelerators, which make a clash of the contrary beams of ions. If in accelerators we will accelerate the ions of deuteron (D) and tritium (T) at their interaction there will be a reaction of synthesis with getting of the alpha-particles - nucleus of helium - 4 ( 4He), neutrons (n) and energy: D + T = 4He + n + 17,6 MeV on the one case of interaction. The warmly, allocated from the chamber of the collider it is possible to use a traditional way - for vaporization of the working medium (for example, waters) and then do use of the pairs of a high pressure.

occupies the area no more than 10 m2 and costs some thousand dollars. In "zero" experiment with nuclear synthesis the sizes of the collider (the volume, where beams collide) can be very small. For example, at his length of 2 sm and diameter of 0,4 sm be expected allocation 25 watt of the heat, i.e. the power density of installation will be 108 watt/m3 (approximately as at the engine of internal combustion). Achievement of such parameters and will mean the physical decision of a problem of controlled thermonuclear synthesis. The getting of the required capacities already cleanly technical a question. The working volume of a reactor, say, can contain necessary quantity of the colliders - the "thermonuclear fuel element". Similar the offers already repeatedly was declared in the scientific literature, however the researches, unfortunately, nobody do. Meanwhile they propose simple experimental verification on the small and inexpensive laboratory stand. The many physicotechnical problems of such experiment are already solved. The estimations showed, that expenses on the such work will be in 10 - 20 thousand times less, than for any other researches in this area. And in case of good luck for people will open of the opportunity of the incomparably more simple decision of a problem of controlled thermonuclear synthesis, than it is promising the all those directions, which are developed now.



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DETAILS FOR INQUISITIVE

Let's count up ENERGY

Let's consider conditions, at which is possible the realization of energetically favourable reaction of nuclear synthesis in system on counter beams. Let in the system be beams of ions deuteron and tritium with energy E1 > 10 keV and concentration n0.
Expenses of energy for acceleration of beams A1 = E1n0. Energy getting as a result of synthesis at repeated collisions of beams A = E0, where - a loss of concentration of fuel due to combustion; E0 = 17,6 MeV - the energy, will be in the single case of reaction of nuclear synthesis.
The condition for the energy-favorable reaction

                         A > GA1,               (1)

where G > 1 - factor of amplification (multiplier) of the energy, he show how the energy received as a result of synthesis, surpasses her expenses for initiation of reaction.
In system on counter beams there are two channels of losses of energy: the electromagnetic radiation arising at accelerated movement of charged particles, and dispersion of particles at elastic collisions with each other and with molecules of residual gas. Inasmuch as in reaction of nuclear synthesis will have participating the ions of the deuteron and tritium, which have weight in 4-5 thousand times exceeding weight of electron, then the losses on radiation in system will be neglible small (they will have value no more than 0,01% from the energy, derived as a result of synthesis). Thus, the basic source of losses of energy in system on counter beams - dispersion of particles. But here the Nature for us has prepared a gift, and be simply a sin not take advantage. The fact is that the section of dispersion in inverse proportion to a square of kinetic energy of relative movement of particles and at energy of ions near 200 keV is comparable with the section of synthesis. Therefore any collision of ions in counter beams should result in reaction of synthesis, and losses on dispersion will be to tend to vanish. At absence of losses on dispersion the interaction of ions of beams in system will occur practically to full combustion of thermonuclear fuel. The energy received in result A
~ E0n0/2 many times over will exceed expenses of energy for initiation of reaction A1 = E1n0. Let's we admit, that, despite of the accepted measures, losses all the same will be great and on one collision of synthesis will exist k scattering collisions.

 

Decrease of concentration of ions ; in system will be defined by combustion of fuel and by the losses on dispersion

.

In this case the condition (1) can be written down:

 

 

where - the energy received as a result 

 

of synthesis; A1 = E1n0 - the energy spent for acceleration of ions.

From here 

 

Taking into account, that 

we receive 

Or

                 (2)

Expression (2) - analogue of criterion Lowson for system on counter beams. At any concentration when it is carried out, reaction of nuclear synthesis will be energetically favourable. 

Let's carry out numerical estimations for 0,2 MeV. 

If G = 1 (the received energy is equal to expenses) k should be less than 43.
Let's we admit, what the system, constructed for realization of reaction of nuclear synthesis appears very imperfect and on one collision of synthesis will have 10 dispersal collisions, i.e.
k = 10. Even in this case G = 4 and the device will work as the generator of energy, to generate on each spent one joule of energy 4 joules. Modern systems on counter beams have very insignificant losses ( k << 1), and sources of ions with energy 0,2 - 1 MeV - already usual industrial equipment. It gives the cause to hope, that try of getting of the controlled reaction of nuclear synthesis on the counter beams the researchers can do in short term and at small expenses. 



(Translation into the English language has executed A.J. Streltsov.)

 

 

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