Study On The Physical Mechanism Of Jet Z - Pin Dynamic Process By Plasma Particle Simulation

The physical model for gas-puff Z-pinch in two-dimensional cylindrical coor-dinates are building according to the the principle of gas-puff Z-pinch. Numerical algorithm of particle-in-cell (PIC) simulation for gas-puff Z-pinch are introduced in detail, and a PIC simulation code was also developed according to the model and algorithm. A light gas-puff Z-pinch driven by a low current has been sim-ulated through the code, and some reasonable results are obtained. The results include the spatio-temporal distributions of current, electromagnetic field, parti-cle positions and density, as well as the trailing mass and current, and particle energy probability distributions.The trajectory of the mass center of particles is close to that of gas-puff Z-pinch, which is presented by the snow-plough model. The simulated curren-t reflects the plasma Z-pinch characteristics, and the simulated magnetic field agrees well with the theoretic value. When the particle system pinches to the axis, the spacial distributions of electron and ion energy become nonuniform, and there are hot spots to form. The energy probability distributions of electron and ion seem to be Maxwellian to some extent, but the most probable energy and the particles with higher energy increase with the pinch time. The electron energy ranges from lOkeV to30keV, and the ions’ranges from1keV to4keV near the stagnation. The electron energy is higher than ion energy by one order of mag-nitude. The electric field force and magnetic field force experienced by electron are almost the same in magnitude, while that experienced by ion is mainly the electric field force. Firstly the electron is accelerated in z direction and gets a velocity, then it moves inwards to the axis in the same time by the Lorentz force. That causes the separation between electron and ion, and in turn a strong elec-tric field is produced. The produced electric field attracts the ions inwards to the electrons. When the electrons gets arrival at the axis, they move inversely due to the static repellency among them, while the ions continue to move initially inwards, and later get into stagnation, and finally collapse. The trailing mass is about20%of the total Z-pinch plasma, and the maximum trailing current is about7%of the driven current.