Variational symplectic algorithm for guiding center dynamics and its application in tokamak geometry

Journal Article · Wed Apr 15 04:00:00 EDT 2009 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3099055· OSTI ID:21277008

Hong, Qin; Xiaoyin, Guan; Tang, William M ^[1]

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1. Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

A variational symplectic integrator for the guiding center motion of charged particles in general magnetic fields is developed to enable accurate long-time simulation studies of magnetized plasmas. Instead of discretizing the differential equations of the guiding center motion, the action of the guiding center motion is discretized and minimized to obtain the iteration rules for advancing the dynamics. The variational symplectic integrator conserves exactly a discrete Lagrangian symplectic structure and globally bounds the numerical error in energy by a small number for all simulation time steps. Compared with standard integrators, such as the fourth order Runge-Kutta method, the variational symplectic integrator has superior numerical properties over long integration time. For example, in a two-dimensional tokamak geometry, the variational symplectic integrator is able to guarantee the accuracy for both the trapped and transit particle orbits for arbitrarily long simulation time. This is important for modern large-scale simulation studies of fusion plasmas where it is critical to use algorithms with long-term accuracy and fidelity. The variational symplectic integrator is expected to have a wide range of applications.

• OSTI ID: 21277008
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 4 Vol. 16; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ALGORITHMS
CHARGED PARTICLES
DIFFERENTIAL EQUATIONS
MAGNETIC FIELDS
PLASMA
PLASMA SIMULATION
RUNGE-KUTTA METHOD
TOKAMAK DEVICES
VARIATIONAL METHODS