The nature of avalanches of super-fluid He-4 in nuclepore

Superfluid He-4 exhibits hysteretic behavior in the porous material Nuclepo re due to capillary condensation, and one observes avalanches in the draini ng for a narrow range of chemical potential. We report results which show t he temperature dependence of the avalanche size distributions and reveal th at the size distributions depend somewhat on the rate of He-4 removal, and we document a qualitative change in the character of the avalanche during c omplete pore draining. (C) 2000 Elsevier Science B.V. All rights reserved.