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Title: Variational symplectic algorithm for guiding center dynamics in the inner magnetosphere

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/1.3589275· OSTI ID:21537818
; ; ;  [1];  [2]
  1. Institute of Space Physics and Applied Technology, Peking University, Beijing 100871 (China)
  2. Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

Charged particle dynamics in magnetosphere has temporal and spatial multiscale; therefore, numerical accuracy over a long integration time is required. A variational symplectic integrator (VSI) [H. Qin and X. Guan, Phys. Rev. Lett. 100, 035006 (2008) and H. Qin, X. Guan, and W. M. Tang, Phys. Plasmas 16, 042510 (2009)] for the guiding-center motion of charged particles in general magnetic field is applied to study the dynamics of charged particles in magnetosphere. 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 VSI conserves exactly a discrete Lagrangian symplectic structure and has better numerical properties over a long integration time, compared with standard integrators, such as the standard and adaptive fourth order Runge-Kutta (RK4) methods. Applying the VSI method to guiding-center dynamics in the inner magnetosphere, we can accurately calculate the particles'orbits for an arbitrary long simulating time with good conservation property. When a time-independent convection and corotation electric field is considered, the VSI method can give the accurate single particle orbit, while the RK4 method gives an incorrect orbit due to its intrinsic error accumulation over a long integrating time.

OSTI ID:
21537818
Journal Information:
Physics of Plasmas, Vol. 18, Issue 5; Other Information: DOI: 10.1063/1.3589275; (c) 2011 American Institute of Physics; ISSN 1070-664X
Country of Publication:
United States
Language:
English