Textural critical velocity of 3He-A in the limit of large magnetic fields

Juha Kopu, R. Schanen, R. Blaauwgeers +4 more

Olli V. Lounasmaa, Juha Simola, Kaj K. Nummila +2 more

Ion-mobility experiments on rotating superfluid 3He–A show that the l-vector texture in the liquid strongly focuses ions to vortex cores and that two different kinds of vortices, with clearly different ion mobilities along their cores, exist in the A phase, depending on the preparation of the rotating state and on the external magnetic field.

Sergei V. Maleev

Francesco Piazza, Lee A. Collins, Augusto Smerzi

V. M. H. Ruutu, Juha Kopu, M. Krusius +4 more

We have measured the critical velocity ${\ensuremath{\upsilon}}_{\mathrm{c}}$ at which ${}^{3}\mathrm{He}\ensuremath{-}\mathrm{A}$ in a rotating cylinder becomes unstable against the formation of quantized vortex lines with continuous (singularity-free) core structure. We find that ${\ensuremath{\upsilon}}_{\mathrm{c}}$ is distributed between a maximum and a minimum limit, which we ascribe to a dependence on the texture of the orbital angular momentun axis $\stackrel{^}{\mathbf{l}}(\mathbf{r})$ in the cylinder. Slow cooldown through ${T}_{\mathrm{c}}$ in rotation yields $\stackrel{^}{\mathbf{l}}(\mathbf{r})$ textures for which the measured ${\ensuremath{\upsilon}}_{\mathrm{c}}$'s are in good agreement with the calculated instability of the expected $\stackrel{^}{\mathbf{l}}$ texture.

Hazime Mori, Hisao Okamoto