139 / 2023-04-14 16:52:22

A Special Poloidal Confinement Electric Field Induced by Strong Converging Shock and its Effects on Converging Process

Inertial Confinement Fusion,Extreme conditions,Molecular dynamics,Electric force field,Ionization

惯性约束聚变物理学 > 其他ICF途径和脉冲功率技术-I

In the Inertial Confinement Fusion (ICF) regime, the irradiation by x-rays or laser beams generates a strong converging shock immediately at the target surface under extreme thermodynamic conditions, which brings great challenges to fusion research. There is a strong ionization effect in front of the shock wave compression wave[1][2]. The diffusion difference between ions and electrons after the wave will cause a large number of free electrons to converge near the ignition pole in advance, which may cause special physical and mechanical effects. Literature reviews indicate that there are few reports about the impact of the ionization effect on the hydrodynamic interface instability and its effects on the convergence process. This paper performed large-scale molecular dynamics simulation of the impact compression ionization effect on cylindrical configurations of the Li/H2 interface under extreme impact loading conditions. It was found that a special poloidal confinement electric field is formed during the convergence process. The additional confinement electric field causes the velocity of the shock wave, material density, and temperature in the central region to be significantly different than those without additional electric confinement. After the shock convergence, the density of plasma at the convergence center remains at its peak in the central region for a period of time under the constraint of a poloidal electric field, forming a density plateau period. A theoretical model for the variation of the electric field and force field at the pole point was established. It reveals the mechanical effects of ionization on converging implosion.