Mass flow through solid 4He induced by the fountain effect

Abstract

Using an apparatus that allows superfluid liquid 4He to be in contact with hcp solid \4he at pressures greater than the bulk melting pressure of the solid, we have performed experiments that show evidence for 4He mass flux through the solid and the likely presence of superfluid inside the solid. We present results that show that a thermomechanical equilibrium in quantitative agreement with the fountain effect exists between two liquid reservoirs connected to each other through two superfluid-filled Vycor rods in series with a chamber filled with solid 4He. We use the thermomechanical effect to induce flow through the solid and measure the flow rate. On cooling, mass flux appears near T = 600 mK and rises smoothly as the temperature is lowered. Near T = 75 mK a sharp drop in the flux is present. The flux increases as the temperature is reduced below 75 mK. We comment on possible causes of this flux minimum.

20 pages, 22 figures, 7 tables

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Cited by in corpus (9)

• Mass flux characteristics in solid 4He for T> 100 mK: Evidence for Bosonic Luttinger Liquid behavior
• Upper limit of supersoldity in solid helium
• Quantum Plasticity and Supersolid Response in Helium-4
• Dissipative superfluid mass flux through solid 4He
• Plasticity induced superclimb in solid Helium-4: Direct and inverse effects
• Supersolid induced by dislocations with superfluid cores (Review article)
• Absence of off-diagonal long-range order in hcp ${}^4$He dislocation cores
• Quantum Phase Transition with a Simple Variational Ansatz
• Anomalously Small Excitation Gaps as a Precursor of Dislocation Core Superfluidity in Solid Helium-4