Electric Drift Effects On Tokamak Energetic Particle Orbits

The movement of Charged particles in magnetic field is one issue that people widelyconcerned, and the trajectories of charged particles in tokamak magnetic field is one focus inmagnetic confinement fusion research. The main task to get the trajectories of charged particles intokamak is to obtain the particle guiding center orbit. There are three ways to handle this problem,one is to use the three constants, one is to solve drift motion equations, the other is solve theHamilton’s equations in OBIT code, but the first two methods ignore the role of the electrostaticpotential and the electric drift effect. In fact, considering the electric drift is the basis of plasmatransport, the trajectories of charged particles in tokamak will be different after including theeffect of electric drift. The motion equations is solved with considering the electric drift in thispaper.Firstly, using the single particle model, the motion of deuterium ion has been simulated inHL-2A tokamak magnetic field configuration without considering electric drift. The results showthat the trajectories of deuterium ion become trapped particles from passing by particles withincreasing angle between the particle initial velocity and the magnetic field. The bounce point ofthe trapped particles will be low with increasing angle. Secondly, by solving the drift motionequations, the trajectories of deuterium ion has also been simulated after considering the effect ofelectric drift. The influence of the effect of electric drift to the trajectories of deuterium ion wasinvestigated. The numerical simulation results show that the trajectories of deuterium ion isdifferent compared to the situation ignoring electric drift. On the other hand, the banana width oftrapped particle become narrower once considering the electric drift.All the above results are in accord with the theoretical analysis and the code we developed isstable. But research work of optimization of the code and the use of the three constants is still inprogress. Our present work lay a foundation for the other method to solve the particle trajectory.