Simulation Research Of Transport And Losses Of Energetic Ions In Tokamak

Tokamak is the most promising device so far to realize magnetic confinement fusion.High-energy ions are not only derived from deuterium tritium fusion and neutral beam heating devices,but also widely exist in the plasma of the tokamak devices,and are also one of the main objects to be bound by magnetic field.Therefore,it is necessary to study the transport and loss of high-energy ions in tokamak.Based on the ORBIT code of the single particle guided center motion,the transport and loss of high energy ions under different magnetic field distributions are discussed by means of the test particle simulation method.The loss of high energy ions in the presence of local magnetic field disturbance in different radial positions inside the Tokamak plasma is studied.The details are as follows:1)Theoretical analysis was carried out on the balance magnetic field and perturbation magnetic field and neutral beam injection physical model in the tokamak device,and a single particle guide orbital equation was derived,and the distribution of high-energy ions and the distribution of magnetic field were calculated respectively.2)Under the condition of no magnetic field disturbance,the more continuous the radial position distribution is,the more the distribution of the angular distribution will be isotropic,and the transport of high-energy ions to the boundary will become more obvious.Under the condition of no magnetic field disturbance or under the condition of MHD magnetic field disturbance,it is helpful to ensure that the safe factor distribution is low and the slope of the safe factor distribution near the boundary can be improved to suppress the transport of high-energy ion to the boundary.3)The local magnetic perturbations can cause the loss of many energetic ions near the central region of the plasma,but they have little effect on the ion losses near the plasma boundary.These energetic ions are trapped ions,and the greater their pitch angle,the easier they are to lose.In addition,the radial position of the local field that causes the maximum loss rate of energetic ions is usually offset from the initial radial position of these loss ions,and this shift is closely related to the energy of these ions.When the local field appears in certain locations,the lower energetic ions have some loss,but the higher energetic ions do not lose.