The two-dimensional diffusive dynamics of test particles in a random electromagnetic field is studied. The synthetic electromagnetic fluctuations are generated through randomly placed magnetised "clouds" oscillating with a frequency ω. We investigate the mean square displacements of particles in both position and velocity spaces. As ω 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 scaling exponents while the process is Gaussian. © Europhysics Letters Association.
Position and velocity space diffusion of test particles in stochastic electromagnetic fields / S., Perri; F., Lepreti; V., Carbone; Vulpiani, Angelo. - In: EUROPHYSICS LETTERS. - ISSN 0295-5075. - 78:4(2007), pp. 40003-40008. [10.1209/0295-5075/78/40003]
Position and velocity space diffusion of test particles in stochastic electromagnetic fields
VULPIANI, Angelo
2007
Abstract
The two-dimensional diffusive dynamics of test particles in a random electromagnetic field is studied. The synthetic electromagnetic fluctuations are generated through randomly placed magnetised "clouds" oscillating with a frequency ω. We investigate the mean square displacements of particles in both position and velocity spaces. As ω 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 scaling exponents while the process is Gaussian. © Europhysics Letters Association.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.