POSITION AND VELOCITY SPACE DIFFUSION OF TEST PARTICLES IN STOCHASTIC ELECTROMAGNETIC FIELDS

The two-dimensional diffusive dynamics of test particles in a random electromagneticfield is studied. The synthetic electromagnetic fluctuations are generated through randomly placedmagnetised “clouds” oscillating with a frequency omega. We investigate the mean square displacements of particles in both position and velocity spaces. As omega increases the particles undergo standard(Brownian-like) motion, anomalous diffusion and ballistic motion in position space. Although in general the diffusion properties in velocity space are not trivially related to those in position space, we find that energization is present only when particles display anomalous diffusion in position space. The anomalous character of the diffusion is only in the non-standard values of the scalingexponents while the process is Gaussian.