Molecular Dynamics Investigation To The Electronic Stopping Power Of Warm Dense Hydrogen

As a method of realizing inertial confinement fusion(ICF),fast ignition has attracted wide attention from researchers in recent years.Warm dense matter(WDM)formed during its process has a significant effect on the stopping power of charged particles,which directly affects the realization of fast ignition.In this paper,the electron force field(eFF)method is used for the first time to study the stopping power of warm dense hydrogen with various temperature for the electrons,which overcomes the coulomb catastrophe problem when solving such problems by classical molecular dynamic(MD)method.The main contents are as follows:Firstly,according to the radial distribution function of hydrogen molecules and the wave packet size function of the electrons in the hydrogen target,the molecular structure and electronic structure of the hydrogen target at different temperatures are qualitatively reflected,and the theoretical explanations and proofs are provided for the effect of temperature on the stopping power of warm dense hydrogen.Then,the eFF method is used to obtain the average stopping power of the hydrogen target for the electrons at different temperatures,and the results are compared with the results calculated by the random phase approximation(RPA)model,the Brown-Preston-Singleton(BPS)model and the local density approximation(LDA)model.Finally,the dynamic behavior of low-energy electrons traverse the hydrogen target is investigated,and the effect of temperature on the stopping power of low-energy electrons in the warm dense hydrogen target is qualitatively analyzed.Numerical calculation results show that the stopping power of warm dense hydrogen for electrons decreases with the increase of the temperature of targets,and the stopping power of low-temperature hydrogen targets is not sensitive to temperature.Compared with the theoretical model(RPA,BPS)that does not consider the electronic structure,the effect of temperature on the stopping power of electrons is completely opposite.Comparing with LDA method based on RPA model,it is show that the effect of temperature on stopping power is consistent.The comparison illustrates that the electronic structure of the hydrogen target(the bound electrons)has a significant influence on its stopping power.The results have a great significance to understand the physical principles such as the dynamic process of electron energy deposition in the fast ignition,and provide an important reference for the development of related theoretical models of stopping power in WDM.