ABSTRACT
All thermonuclear reactions between light nuclei have cross sections which vanish below an energy threshold of the order of at least 10 keV. In a fusion reactor, confinement of a hot plasma achieved for a sufficiently long time to permit the fusion reactions to develop. It defines the criteria that plasma must satisfy for a positive energy balance expected. A certain energy investment is necessary to raise the gas from its ambient temperature to the functioning temperature. It is also necessary to take account of energy losses due to radiation and to particles which escape confinement. In everything which follows, the temperatures expressed in energy units, which permits us to ignore Boltzmann's constant. In thermodynamic equilibrium a plasma viewed as a mixture of two extremely hot gases consisting of ne atomic electrons and n1 ions per unit volume. Physics of plasmas have seen that there is good hope of obtaining controlled fusion in the laboratory in the near future.
