Thermal conductivity of superfluid $^3$He-B in a tubular channel down to 0.1$T_c$ at the $^4$He crystallization pressure
| Autor: | Riekki, T. S., Tuoriniemi, J. T., Sebedash, A. P. |
|---|---|
| Rok vydání: | 2019 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1007/s10909-019-02305-4 |
| Popis: | We studied the thermal conductivity of superfluid $^3$He in a 2.5 mm effective diameter and 0.15 m long channel connecting the two volumes of our experimental assembly. The main volume contained pure solid $^4$He, pure liquid $^3$He and saturated liquid $^3$He-$^4$He mixture at varying proportions, while the separate heat-exchanger volume housed sinter and was filled by liquid $^3$He. The system was cooled externally by a copper nuclear demagnetization stage, and, as an option, internally by the adiabatic melting of solid $^4$He in the main volume. The counterflow effect of superfluid just below the transition temperature $T_c$ resulted in the highest observed conductivity about five times larger than that of the normal fluid at the $T_c$. Once the hydrodynamic contribution had practically vanished below $0.5T_c$, we first observed almost constant conductivity nearly equal to the normal fluid value at the $T_c$. Finally, below about $0.3T_c$, the conductivity rapidly falls off towards lower temperatures. Comment: 11 pages, 4 figures, 1 table |
| Databáze: | arXiv |
| Externí odkaz: |
|