Explicit integrators for the magnetized equations of motion in Particle in Cell codes

• Main Authors: Hutchinson, Ian H. (Contributor), Patacchini, Leonardo (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Nuclear Science and Engineering (Contributor), Massachusetts Institute of Technology. Plasma Science and Fusion Center (Contributor)
• Format: Article
• Language: English
• Published: Academic Press, 2010-09-28T12:46:50Z.
• Subjects: Article
• Online Access: Get fulltext

 A new explicit time-reversible orbit integrator for the equations of motion in a static homogeneous magnetic field - called Cyclotronic integrator - is presented. Like Spreiter and Walter's Taylor expansion algorithm, for sufficiently weak electric field gradients this second order method does not require a fine resolution of the Larmor motion; it has however the essential advantage of being symplectic, hence time-reversible. The Cyclotronic integrator is only subject to a linear stability constraint ([OmegaDelta t] < pi, [Omega] being the Larmor angular frequency), and is therefore particularly suitable to electrostatic Particle In Cell codes with uniform magnetic field where [Omega]is larger than any other characteristic frequency, yet a resolution of the particles' gyromotion is required. Application examples and a detailed comparison with the well-known (time-reversible) Boris algorithm are presented; it is in particular shown that implementation of the Cyclotronic integrator in the kinetic codes SCEPTIC and Democritus can reduce the cost of orbit integration by up to a factor of ten.