Driving Rate Effects on Crackling Noise

Many systems respond to slowly changing external conditions with crackling noise, created by avalanches or pulses of a broad range of sizes. Examples range from Barkhausen Noise in magnets to earthquakes. Here we discuss how the scaling behavior of the avalanche size and duration distribution and the power spectra of this noise depend on the rate at which the external conditionsare changed. We derive an exponent inequality as a criteria for the relevance of adding a small driving rate to the adiabatic model. We use the zero temperature nonequilibrium random field Ising model to test our results, which are expected to be applicable to a large class of systems with crackling noise. They also agree with recent experiments on Barkhausen noise in various materials.