Current noise in long diffusive SNS junctions in the incoherent multiple Andreev reflections regime

Spectral density of current fluctuations at zero frequency is calculated for a long diffusive SNS junction with low-resistive interfaces. At low temperature, TΔ, the subgap shot noise approaches linear voltage dependence, S=(2/3R)(eV+2Δ), which is the sum of the shot noise of the normal conductor and voltage independent excess noise. This result can also be interpreted as the 1/3-suppressed Poisson noise for the effective charge q=e(1+2Δ/eV) transferred by incoherent multiple Andreev reflections (MAR). At higher temperatures, anomalies of the current noise develop at the gap subharmonics, eV=2Δ/n. The crossover to the hot electron regime from the MAR regime is analyzed in the limit of small applied voltages.