Magnetic field fluctuations in an array of randomly directed circular currents

We study the magnetic field fluctuations generated by an array of circular currents with axial symmetry. The fluctuations are induced via the random orientation of the current in each ring. By increasing the number of rings per unit length, we observe a transition from a continuous to a stratified spectrum of possible magnetic field values at a fixed location on the symmetry axis. A semi-analytical description of the properties characterising this transition is obtained revealing the competition between long range and short range contributions in this device. Our work provides a possibility to manipulate magnetic fields in a controllable and experimentally easily accessible manner, a task which can be of interest for accelerator and mesoscopic physics. Copyright EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2013