Event-by-event fluctuations of magnetic and electric fields in heavy ion collisions

Abstract

We show that fluctuating proton positions in the colliding nuclei generate, on the event-by-event basis, very strong magnetic and electric fields in the direction both parallel and perpendicular to the reaction plane. The magnitude of E and B fields in each event is of the order of $m_{\pi }^2\approx {10}^{18}$ Gauss. Implications on the observation of electric dipole in heavy ion collisions is discussed, and the possibility of measuring the electric conductivity of the hot medium is pointed out.