Browsing by Author "Avenel, O."
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- Coupling of zero sound to the real squashing mode in rotating 3B
School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(1989) Salmelin, Riitta; Pekola, Jukka P.; Manninen, A. J.; Torizuka, K.; Berglund, M. P.; Kyynäräinen, J. M.; Lounasmaa, O. V.; Tvalashvili, G. K.; Magradze, O. V.; Varoquaux, E.; Avenel, O.; Mineev, V. P.Rotation of superfluid 3B in an magnetic field enhances the coupling of the nonzero mJ substrates of the real squashing collective mode to the zero sound, and the fivefold line splitting becomes observable even when H is parallel to Ω and to the direction of sound propagation. Equilibrium vortex lattices and vortex-free states can be distinguished by their characteristic absorption spectra. The dependence of the sound attenuation on the angular velocity in magnetic fields up to 32 mT is reported; the data are qualitatively compared with theory. - Coupling of zero sound to the real squashing mode in rotating 3He-B
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(1989-08-07) Salmelin, R. H.; Pekola, J. P.; Manninen, A. J.; Torizuka, K.; Berglund, M. P.; Kyynäräinen, J. M.; Lounasmaa, O. V.; Tvalashvili, G. K.; Magradze, O. V.; Varoquaux, E.; Avenel, O.; Mineev, V. P.Rotation of superfluid B3 in an magnetic field enhances the coupling of the nonzero mJ substrates of the real squashing collective mode to the zero sound, and the fivefold line splitting becomes observable even when H is parallel to and to the direction of sound propagation. Equilibrium vortex lattices and vortex-free states can be distinguished by their characteristic absorption spectra. The dependence of the sound attenuation on the angular velocity in magnetic fields up to 32 mT is reported; the data are qualitatively compared with theory. - Detection of the Rotation of the Earth with a Superfluid Gyrometer
School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(1997) Avenel, O.; Hakonen, Pertti J.; Varoquaux, E.The effect of the rotation of the Earth, Ω⊕, on a superfluid resonator equipped with a 4.0 cm exp 2 rotation pickup loop and with a microaperture is reported. The velocity circulation induced in the loop by the rotation is detected by phase-slippage techniques. The magnitude of Ω⊕ is measured to better than 1%, and the north direction to ±0.5° for a 10 h observation time. This experiment is the superfluid counterpart of interferometric measurements based on the Sagnac effect. - Evidence for single-vortex pinning and unpinning events in superfluid 4He
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(1998-10-19) Hakonen, P.; Avenel, O.; Varoquaux, E.We have observed two critical velocity levels for phase slips in superfluid 4He at temperatures between 14 and 44 mK, due to microparticles formed in the cell at low temperature. We interpret these observations as evidence for pinning and unpinning events of single vortices of nanometric size. From a study of the lifetime and unpinning velocities of the pinned vortices, we are led to conclude that unpinning takes place by quantum tunneling. - Evidence for Single-Vortex Pinning and Unpinning Events in Superfluid 4He
School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(1998) Hakonen, Pertti J.; Avenel, O.; Varoquaux, E.We have observed two critical velocity levels for phase slips in superfluid 4He at temperatures between 14 and 44 mK, due to microparticles formed in the cell at low temperature. We interpret these observations as evidence for pinning and unpinning events of single vortices of nanometric size. From a study of the lifetime and unpinning velocities of the pinned vortices, we are led to conclude that unpinning takes place by quantum tunneling.