Hydrodynamic properties and structure of strong shock waves in classical dense helium are simulated using non-equilibrium molecular dynamics methods. The shock speed in the simulation reaches 100 km/s and the Mach num...Hydrodynamic properties and structure of strong shock waves in classical dense helium are simulated using non-equilibrium molecular dynamics methods. The shock speed in the simulation reaches 100 km/s and the Mach number is over 250, which are close to the parameters of shock waves in the implosion process of inertial confinement fusion. The simulations show that the high-Mach-number shock waves in dense media have notable differences from weak shock waves or those in dilute gases. These results will provide useful information on the implosion process, especially the structure of strong shock wave front, which remains an open question in hydrodynamic simulations.展开更多
Direct numerical simulation of intense laser-solid interactions is still of great challenges, because of the many coupled atomic and plasma processes, such as ionization dynamics, collision among charged particles and...Direct numerical simulation of intense laser-solid interactions is still of great challenges, because of the many coupled atomic and plasma processes, such as ionization dynamics, collision among charged particles and collective electromagnetic fields, to name just a few. Here, we develop a new particle-in-cell （PIC） simulation code, which enables us to calculate laser-solid interactions in a more realistic way. This code is able to cover almost ＇all＇ the coupled physical processes. As an application of the new code, the generation and transport of energetic electrons in front of and within the solid target when irradiated by intense laser beams are studied. For the considered case, in which laser intensity is 1020 W. cm-2 and pre-plasma scale length in front of the solid is 10 Izm, several quantitative conclusions are drawn： （i） the collisional damping （although it is very weak） can significantly affect the energetic electrons generation in front of the target, （ii） the Bremsstrahlung radiation will be enhanced by 2-3 times when the solid is dramatically heated and ionized, （iii） the ＇cut-off＇ electron energy is lowered by an amount of 25% when both collision damping and Bremsstrahlung radiations are included, and （iv） the resistive electromagnetic fields due to Ohmic heating play nonignorable roles and must be taken into account in such interactions.展开更多
文摘Hydrodynamic properties and structure of strong shock waves in classical dense helium are simulated using non-equilibrium molecular dynamics methods. The shock speed in the simulation reaches 100 km/s and the Mach number is over 250, which are close to the parameters of shock waves in the implosion process of inertial confinement fusion. The simulations show that the high-Mach-number shock waves in dense media have notable differences from weak shock waves or those in dilute gases. These results will provide useful information on the implosion process, especially the structure of strong shock wave front, which remains an open question in hydrodynamic simulations.
基金supported by the Science Challenge Project(No.TZ2016005)the National Natural Science Foundation of China(Nos.11605269,11674341,and 11675245)+1 种基金the National Basic Research Program of China(No.2013CBA01504)the financial support from German Academic Exchange Service(DAAD)and China Scholarship Council(CSC)
文摘Direct numerical simulation of intense laser-solid interactions is still of great challenges, because of the many coupled atomic and plasma processes, such as ionization dynamics, collision among charged particles and collective electromagnetic fields, to name just a few. Here, we develop a new particle-in-cell （PIC） simulation code, which enables us to calculate laser-solid interactions in a more realistic way. This code is able to cover almost ＇all＇ the coupled physical processes. As an application of the new code, the generation and transport of energetic electrons in front of and within the solid target when irradiated by intense laser beams are studied. For the considered case, in which laser intensity is 1020 W. cm-2 and pre-plasma scale length in front of the solid is 10 Izm, several quantitative conclusions are drawn： （i） the collisional damping （although it is very weak） can significantly affect the energetic electrons generation in front of the target, （ii） the Bremsstrahlung radiation will be enhanced by 2-3 times when the solid is dramatically heated and ionized, （iii） the ＇cut-off＇ electron energy is lowered by an amount of 25% when both collision damping and Bremsstrahlung radiations are included, and （iv） the resistive electromagnetic fields due to Ohmic heating play nonignorable roles and must be taken into account in such interactions.
