Properties Of Proton Bean And Electron Beam Confined With A Magnetic Mirror Field

A magnetic mirror configuration can be observed in many magnetized plasmas,including large devices for studying the thermonuclear fusion,the Earth's magnet sphere,etc.The fusion research in open-ended systems has led to a comprehensive study of plasma confinement in magnetic mirrors.The motion of non-neutral plasma beams in magnetic mirrors is also a key point in the study of magnetic mirror.The research contents include confinement,radial and axial evolution and instability of non-neutral plasma beams in magnetic mirrors.At the same time,it is very important the effects of different magnetic field configurations of mirror on confinement time.In this paper,Particle-In-Cell algorithm is used to simulate the confinement,radial and axial evolution of drifting Maxwell-distributed non-neutral plasma beams in a simple magnetic mirror by VSim software.In the second chapter,PIC algorithm and VSim software are briefly introduced.Firstly,we introduce the basic idea and process of particle simulation method.It includes the discretization of the physics of plasma and field,meshing,time step selection,and the driving process of charged particles in electromagnetic field.Secondly,we introduce the basic framework of VSim software.In the third and fourth chapters of this paper,By using the particle-in-cell(PIC)simulation method,the proton beam in magnetic mirror is investigated in the present paper.First,We define two physical quantities to describe the confinement effects of mirror for ion beam.One is loss rate ??N_lost/N₀,where N_lost is the number of leaked particles from the mirror and N₀ is the number of the initial particles.According to the curve ?-t,we define confinement time ?_m.We have ???₀(1-e^-t/?_mm(8),where ?₀ is the maximal value of the loss rate.Dependence of the loss rate or the confinement time on the parameters of both magnetic mirror and the proton beam are given.It is found that the larger the mirror ratio,the less the loss rate,or the longer the confinement time.The appropriate proton beam velocity and other parameters of the protons can significantly improves the confinement time of the mirror and improve the efficiency of confinement.The movements of the charged particles are also studied in the mirror.