Radiative noise in circuits with inductance

Using the general idea of the fluctuation-dissipation theorem we study a ne w contribution to the voltage fluctuations which is associated with the pre sence of radiation resistance. We consider the particular case of a solenoi d immersed in a cavity with equilibrium radiation at temperature T. We prov e that these new fluctuations are generated by the random magnetic field pr esent in the cavity. These magnetic voltage fluctuations are shown to be ex perimentally distinguishable from the voltage fluctuations associated with the well known Nyquist noise. Accordingly we suggest feasible experiments t o measure this magnetic noise. All the calculations an made within the cont ext of Stochastic Electrodynamics, a theory in which the vacuum zero-point field is taken as a real electromagnetic field. We also study the average e nergy of an RLC circuit in thermodynamic equilibrium with the radiation. (C ) 2001 Elsevier Science B,V. All rights reserved.