Large-stepsize integrators for charged particles in a strong magnetic field

by Prof. Ernst Hairer (Université de Genève)

Thursday 20 Apr 2023, 14:30 → 15:30 Europe/Rome

Rectorate/Building-Auditorium (GSSI)

Abstract:

 

This talk considers the numerical treatment of the differential equation that describes the motion of electric particles in a strong magnetic field. A standard integrator is the Boris algorithm which, for small stepsizes, can be analysed by classical techniques. For a strong magnetic field the solution is highly oscillatory and the numerical integration is more challenging. New modifications of the Boris algorithm are discussed, and their accuracy and long-time behaviour are studied with means of modulated Fourier expansions. Emphasis is put on the situation where the stepsize is proportional to (or larger than) the wavelength of the oscillations.

The presented results have been obtained in collaboration with Christian Lubich.