A thermonuclear reaction is a nuclear reaction between light atomic nuclei that proceeds at a very high temperature (above 108 K). In this case, a large amount of energy is formed in the form of neutrons with a high energy index and photons - particles of light.
High temperatures, and therefore the large energies of the nuclei that collide, are necessary to overcome the electrostatic barrier. This barrier is due to the mutual repulsion of nuclei (like particles of the same name). Otherwise, they would not be able to approach a distance sufficient for the action of nuclear forces (and this is about 10-12 cm).
The thermonuclear reaction is the process of the formation of nuclei, which are strongly interconnected, from more loose ones. Almost all such reactions relate to fusion (synthesis) of lighter nuclei into heavy ones.
The kinetic energy needed to overcome mutual repulsion must increase with increasing nuclear charge. Therefore, the easiest way is the synthesis of light nuclei with a small electric charge.
In nature, a thermonuclear reaction can occur only in the bowels of stars. For its implementation in terrestrial conditions it is necessary to heat the substance in one of the possible ways:
- nuclear explosion;
- intense particle bombardment;
- powerful laser pulse or gas discharge.
The thermonuclear reaction that occurs in the bowels of stars plays a crucial role in the evolution of the Universe. Firstly, the nuclei of future chemical elements are formed from hydrogen in stars, and secondly, it is the energy source of stars.
Thermonuclear Reactions in the Sun
On the Sun, the reactions of the proton-proton cycle, when one nucleus of helium is born from four protons, act as the main source of energy. The energy that is released during the synthesis is carried away by the forming nuclei, neutrons, neutrinos and quanta of electromagnetic radiation. By studying the neutrino flux coming from the Sun, scientists can establish the nature and intensity of the nuclear reactions that occur at its center.
The average intensity of the solar energy release by Earth standards is negligible - only 2 erg / s * g (per 1 gram of solar mass). This value is much less than the rate of electrowinning in a living organism in the process of standard metabolism. And only thanks to the enormous mass of the Sun (2 * 1033 g) the total amount of power radiated by it is such a gigantic quantity as 4 * 1028 W.
Due to the enormous size and mass of the Sun and other stars, the problem of plasma confinement and thermal insulation is solved in them perfectly: reactions proceed in a hot core, and heat transfer occurs from a colder surface. This is only why stars can produce energy so efficiently in processes as slow as the proton-proton cycle. Under terrestrial conditions, such reactions are practically impracticable.
Thermonuclear energy is the foundation of the future
On our planet, it makes sense to apply and use only the most effective of thermonuclear reactions - first of all, the synthesis of helium from the nuclei of leuterium and tritium. Such reactions on a comparatively large scale are feasible so far only in test explosions of hydrogen bombs. Nevertheless, ever new developments are constantly being conducted with the aim of efficiently obtaining peaceful electricity. Traditional nuclear energy uses the decay reaction, and fusion is involved in fusion. Moreover, the thermonuclear reaction has a number of undeniable advantages over the nuclear decay reaction.
1. In thermonuclear reactions, it is possible to avoid the emission of radioactive radiation, since in this case the “pure” light energy is the energy product.
2. In terms of the amount of energy received, thermonuclear processes far surpass traditional atomic reactions that are used in modern reactors.
3. In order to maintain the nuclear decay reaction, constant monitoring of the neutron flux is necessary, otherwise an uncontrolled chain reaction that is dangerous for humanity may follow. Instead of a neutron flux, high temperature is used to obtain thermonuclear energy, therefore, such risks disappear.
4. Fuel for thermonuclear reactions is harmless, in contrast to the decay products of nuclear reactors.
Not so long ago, American scientists managed to create a working model of a thermonuclear reaction in which the energy yield is one hundred times higher than energy consumption. This is a good application for the further successful "taming" of fusion energy.