"Method to integrate full particle orbit in toroidal plasmas"

 

 

 

It is important to integrate full particle orbit accurately to a long time in a fusion device such as tokamak when studying charged particle dynamics in electromagnetic waves with frequency higher than the cyclotron frequency. We derive the form of the Boris scheme using magnetic coordinates, which can be used effectively for long time scale integration of the cyclotron orbit in toroidal plasmas. The new method has been verified in a toroidal simulation in the absence of the high frequency waves. The full particle orbit calculation recovers the guiding center banana orbit. This method has better numeric properties than the conventional Runge-Kutta method in conserving particle energy and magnetic moment. The toroidal precession frequency is found to match that from the guiding center simulation. Many other important physics phenomena, such as the EXB drift, the Ware pinch effect and the neoclassical polarization drift are also verified by the full orbit simulation.