We study the dissipative currents in 3He weak links subjected to pressure biases. Recent experiments on the dc currents through an array-type weak link were only analyzed by phenomenological models . We show that the order of magnitude of these currents may be accounted for by the well-known process of "multiple Andreev reflections" , where the number of Andreev reflections is limited by inelastic processes due to quasiparticle-quasiparticle collisions. In this case the current-pressure (I-P) characteristics should be strictly linear and independent of textural configurations in the low-pressure regime (see figure). However, the observed I-P curves were strongly nonlinear and different for the "H" and "L" states which have previously been interpreted as two different textural states [3,4]. We show that at least part of these deviations can be explained by the anisotextural effect [3,4], which was used to explain the existence of the "π states" in the same experimental setup.
Back to helium theory page30.8.2005, Erkki Thuneberg, Email