aqora

Nonlinear dynamics of Josephson vortices in merging superfluid rings

Artem Oliinyk, Boris A. Malomed, A. I. Yakimenko

arXiv:1908.02468Communications in Nonlinear Science and Numerical SimulationNov 13, 201915 citations

Cascade of Solitonic Excitations in a Superfluid Fermi Gas: From Solitons and Vortex Rings to Solitonic Vortices

Mark Ku, Biswaroop Mukherjee, Tarik Yefsah +1 more

Bulletin of the American Physical SocietyJun 9, 20150 citations

Scattering of Superfluid Vortex Rings

Joel Koplik, Herbert Levine

The time evolution and scattering interactions of superfluid vortex rings are studied using the Gross-Pitaevskii model, in order to consider the maintenance and generation of vorticity in superfluid flows, and to compare ring dynamics in Navier-Stokes and superfluids. For a single ring, we verify previous analytic results on stability and the value of the translation velocity. When two vortex rings scatter, we generically observe merger and subsequent breakup in cases of close approach. Depending on the initial conditions, the final state can contain zero, two, or more final rings.The time evolution and scattering interactions of superfluid vortex rings are studied using the Gross-Pitaevskii model, in order to consider the maintenance and generation of vorticity in superfluid flows, and to compare ring dynamics in Navier-Stokes and superfluids. For a single ring, we verify previous analytic results on stability and the value of the translation velocity. When two vortex rings scatter, we generically observe merger and subsequent breakup in cases of close approach. Depending on the initial conditions, the final state can contain zero, two, or more final rings.

Physical Review LettersJun 17, 199654 citations

Vortex Ring Formation in a Superfluid

Sergei V. Iordanskii

Journal of Experimental and Theoretical PhysicsAug 1, 196576 citations

Investigation of Quantum Turbulence in Superfluid (_^4)HeUsing Injected Ions and ?He?_2^* Molecules in the ZeroTemperature Limit

Fatemeh Pakpour

The decay of quantum turbulence in superfluid (_^4)He in the zero temperature limit wasinvestigated. Quantum turbulence was created by impulsive spin-down from a specific angular velocity to rest. A measurement of the vortex line density was performed using the scattering of charged vortex rings. The vortex line density decayed as L ? t^(-3/2) which is the characteristic of quasiclassical turbulence forced at large length scales. The interaction of metastable spin-triplet ?He?_2^* molecules with quantized vortex lines in superfluid (_^4)He at temperatures below 200 mK was studied too. The molecules were generated during an injection of electrons from a sharp metal tip at high voltage. They were detected as a current into a metal collector after ionization upon colliding with the collector surface. The detected current was suppressed by even a small rotation indicating the trapping of the molecules on quantized vortices. The presence of (_^3)He impurities at the level of 0.3 ppb strongly suppressed the detected signal. The temperature dependence of the detected signal showed a sharp peak, most probably associated with the condensation of (_^3)He atoms on vortex cores. The time of flight of the molecules as a function of temperature was measured. It was observed that there are three regimes for ?He?_2^* molecules transportation in superfluid (_^4)He : ballistic regime for T 200 mK, and an intermediate regime between them. The vortex lines were created by either rotation or ion injection. The trapping diameter of the molecules on quantized vortices was found to be 96 � 6 nm at pressure of 0.1 bar and 27 � 5 nm at 5.0 bar. It was also demonstrated that a tangle of vortices moving in superfluid (_^4)He are capable of conveying the ?He?_2^* molecules through the drift region.The decay of quantum turbulence in superfluid (_^4)He in the zero temperature limit wasinvestigated. Quantum turbulence was created by impulsive spin-down from a specific angular velocity to rest. A measurement of the vortex line density was performed using the scattering of charged vortex rings. The vortex line density decayed as L ? t^(-3/2) which is the characteristic of quasiclassical turbulence forced at large length scales. The interaction of metastable spin-triplet ?He?_2^* molecules with quantized vortex lines in superfluid (_^4)He at temperatures below 200 mK was studied too. The molecules were generated during an injection of electrons from a sharp metal tip at high voltage. They were detected as a current into a metal collector after ionization upon colliding with the collector surface. The detected current was suppressed by even a small rotation indicating the trapping of the molecules on quantized vortices. The presence of (_^3)He impurities at the level of 0.3 ppb strongly suppressed the detected signal. The temperature dependence of the detected signal showed a sharp peak, most probably associated with the condensation of (_^3)He atoms on vortex cores. The time of flight of the molecules as a function of temperature was measured. It was observed that there are three regimes for ?He?_2^* molecules transportation in superfluid (_^4)He : ballistic regime for T 200 mK, and an intermediate regime between them. The vortex lines were created by either rotation or ion injection. The trapping diameter of the molecules on quantized vortices was found to be 96 � 6 nm at pressure of 0.1 bar and 27 � 5 nm at 5.0 bar. It was also demonstrated that a tangle of vortices moving in superfluid (_^4)He are capable of conveying the ?He?_2^* molecules through the drift region.

Sep 24, 20140 citations

Knots and Coils in Superfluid Vortices

Dustin Kleckner, Davide Proment, Martin W. Scheeler +1 more

Bulletin of the American Physical SocietyNov 23, 20140 citations

Scattering of Line-Ring Vortices in a Superfluid

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