Energy-preserving algorithm for gyrocenter dynamics of charged particles

Gyrocenter dynamics of charged particles plays a fundamental and important role in plasma physics, which requires accuracy and conservation in a long-time simulation. Variational symplectic algorithms and canonicalized symplectic algorithms have been developed for gyrocenter dynamics. However, variational symplectic methods are always unstable, and canonicalized symplectic methods need coordinates transformation case by case, which is usually difficult to find. Based on the fact that the Hamiltonian function describing the energy of the system is invariant, we develop energy-preserving algorithms for gyrocenter dynamics systematically using the discrete gradient method. The given integrators have significant advantages in preserving energy and efficiency over long-time simulations, compared with non-symplectic methods and canonicalized symplectic algorithms.