| The average thermonuclear reaction rate is one essential characteristic quantity of thermonuclear fusion reaction efficiency. It is a basic physical quantity to describe many other important physical quantities. Normally, the fusing particles are in the thermal dynamic balance state with the same temperature, so we can adopt an average thermonuclear reaction rate only related to temperature, to describe the reaction of the fusion system. However, under some extreme conditions, particles participating in fusion reaction would deviate off the Maxwell velocity distribution and be in the non-thermal dynamic balance state. It will lead to larger deviation if we only use the method of thermal balance since it ignores the influence of non-equilibrium effect on fusion reaction process.There are some work on calculation of the average thermonuclear reaction rate under non-thermal dynamic balance state, but only applied to the special case with one particle in the non-thermal equilibrium and another in thermal equilibrium state. In this case, we usually use speed group-dividing method to calculate the average thermonuclear reaction rate, but there are some shortcomings in accuracy and range of application. So the method for calculating the average thermonuclear reaction rate of non-thermal dynamic equilibrium needs further investigation.Based on this, we carry out the as following work:First, we use the Fokker-Planck transport theory to study the moderated behavior of D particles. The high energy D particles in the monoenergetic or Maxwell distribution is incident to background of T particles, we can get a non-Maxwell steady-state distribution of moderated D particle. In the subsequent works, we will calculate and analyze the average rate of thermonuclear reaction rate using those non-equilibrium distributions.Secondly, considering the average thermonuclear reaction rate under the non-equilibrium distribution we are forced to the calculation of the six dimensional integrals, for which the numerical integration method is not suitable. However, Monte Carlo method has the advantages of efficient computation of multidimensional integrals, so we apply this method to arbitrary distribution of average thermonuclear reaction rates. For typical examples, the results from Mote Carlo method agree with that from the direct integral method and speed group-dividing method, which confirms the higher precision and wider application of the new method.Finally, we calculate the average thermonuclear reaction rate of D particles before and after they slowing down, and analyze results of the non-equilibrium effect on average thermonuclear reaction rate of DT system. The results show that the non-equilibrium effect has significant influence on average thermonuclear reaction rate.. |
