Reconnection Of Self-generated Magnetic Field In Laser-plasma Research

Achieveing the controlled nuclear fusion energy to be used,this requires that we must to improve the condition of magnetic confinement and the method of plasma heating.The plasma physics has been becomed informational content of a new physical discipline,and the latest laser plasma physics is nearly thirty or forty year formation and rapid development of a branch.Using the interaction between high energy high power density of laser and solid target,the target material is heated by the laser,and finally has been ionization to high temperature plasma state that the temperature about keV magnitude.Due to the interaction between high laser and plasma,it will produce hot energy electron that can cause strong anisotropy pressure in the internal tartget.This will lead to the deformation of target surface and compression failure.So the realization of direct-drive inertial confinement fusion requires a symmetric compression of the target to achieve the ignition conditions.But if the target has flaws,such as the nonuniformity of drive laser irradiation and the asymmetry of the target physical characteristics.Then those flaws will be magnified by the hydrodynamic instability mechanisms rapid,and the symmetrical compression effect of the target will be serious influenced,finally leading to the ignition failure.In addition to the influence of initial conditions on the target of symmetry compression,the interaction between laser and target results in the asymmetry of tartget characteristics will also destroy the compression process.In addition,analyzing the generalized ohm's law,we found that the studies of the electronic pressure tensor of the generalized ohm's law are good for understanding and awareness of magnetic reconnection.In the process of magnetic reconnection,due to the manetic free energy is released in the current sheets.The magnetic free energy of be released will transform into the plasma kinetic energy and heat energy.By this way,the effect of acceleration and heating of plasma be improved.The study for collisionless magnetic reconnection is a new direction that developed from reconnection theory in last decade.Because of the development of computer numerical simulation,the collisionless magnetic reconnection was proposed.After that,a large amount of the observation data and experimental data had proved that the collisionless magnetic reconnection theory isreliable.In this paper,firstly,we briefly introduce the related knowledge about plasma and one dimensional particle simulation program.Sencondly,the generalized ohm's law was theoretical derivation by us.According to the analysis of the generalized ohm's law,we found the electronic pressure tensor is very important for reconnection.Using the one dimensional particle simulation program,we studied the anisotropic pressure tensor of hot electrons that are produced by a short laser pluse and then propagate into the over dense plasma.In the presence of background magnetic field conditions,we also studied the characteristics of the anisotropic pressure in the area of over dense plasma.It is useful for us to understand of magnetic reconnection in depth.