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In the field of cryogenics, helium [He] is utilized for a variety of reasons. The combination of helium’s extremely low molecular weight and weak interatomic reactions yield interesting properties when helium is cooled below its critical temperature of 5.2 K to form a liquid. Even at absolute zero (0K), helium does not condense to form a solid under ambient pressure. In this state, the zero point vibrational energies of helium are comparable to very weak interatomic binding interactions, thus preventing lattice formation and giving helium its fluid characteristics. Within this liquid state, helium has two phases referred to as helium I and helium II. Helium I displays thermodynamic and hydrodynamic properties of classical fluids, along with quantum characteristics. However, below its lambda point of 2.17 K, helium transitions to He II and becomes a quantum superfluid with zero viscosity.
References
- ↑ Herman, Robert; Prigogine, Ilya (April 1979). "A Two-Fluid Approach to Town Traffic" (PDF). Science . 204 (4389): 148–151. Bibcode:1979Sci...204..148H. doi:10.1126/science.204.4389.148. PMID 17738075. S2CID 20780759. Archived from the original (PDF) on 2012-03-30.
- ↑ Khalatnikov, I.M. (2000). An Introduction to the Theory of Superfluidity. Westview Press. ISBN 978-0738203003.
- ↑ Balibar, S. (2017). "Laszlo Tisza and the two-fluid model of superfluidity". Comptes Rendus Physique. 18 (9–10): 586–591. doi:10.1016/j.crhy.2017.10.016.
- ↑ Barna, I.F.; Mátyás, L. (2021). "Analytic Solutions of a Two-Fluid Hydrodynamic Model". Mathematical Modelling and Analysis. 26 (4): 582–590. arXiv: 2004.09815 . doi:10.3846/mma.2021.13637.