Vortex multiplication in applied flow: A precursor to superfluid turbulence.
A surface-mediated process is identified in 3He-B which generates vortices at a roughly constant rate. It precedes a faster form of turbulence where intervortex interactions dominate. This precursor becomes observable when vortex loops are introduced in low-velocity rotating flow at sufficiently low mutual friction dissipation at temperatures below 0.5Tc. Our measurements indicate that the formation of new loops is associated with a single vortex interacting in the applied flow with the sample boundary. Numerical calculations show that the single-vortex instability arises when a helical Kelvin wave expands from a reconnection kink at the wall and then intersects again with the wall.
Finne
A P
AP
Low Temperature Laboratory, Helsinki University of Technology, P.O. Box 2200, FIN-02015 HUT, Finland.
Eltsov
V B
VB
Eska
G
G
Hänninen
R
R
Kopu
J
J
Krusius
M
M
Thuneberg
E V
EV
Tsubota
M
M