TY - JOUR

T1 - Temperature-dependent vortex nucleation in isotopically pure superfluid 4He.

AU - Nancolas, G. G.

AU - McClintock, Peter V. E.

AU - Moss, F. E.

AU - Bowley, R. M.

PY - 1981

Y1 - 1981

N2 - We have investigated the temperature dependence of the rate nu which negative ions nucleate vortex rings in isotopically pure superfluid 4He. Measurements of nu(E,T) are presented for a pressure of 23 bar with electric fields E in 5.8 < E < 1.2 x l0^6 V m-l and temperatures T in 0.3 < T < 0.8 K. Provided that due allowance is made for the drag arising from ion-excitation scattering, (nu - nu0) is proportional to Nr, where Nr is the thermal roton density and nu0 is the temperature-dependent limiting value of nu below 0.5 K. We show that this discovery is consistent with the existence of an additional vortex nucleation mechanism, characterised by a critical velocity reduced by roton absorption, but ultimately determined by a requirement for the conservation of energy and momentum.

AB - We have investigated the temperature dependence of the rate nu which negative ions nucleate vortex rings in isotopically pure superfluid 4He. Measurements of nu(E,T) are presented for a pressure of 23 bar with electric fields E in 5.8 < E < 1.2 x l0^6 V m-l and temperatures T in 0.3 < T < 0.8 K. Provided that due allowance is made for the drag arising from ion-excitation scattering, (nu - nu0) is proportional to Nr, where Nr is the thermal roton density and nu0 is the temperature-dependent limiting value of nu below 0.5 K. We show that this discovery is consistent with the existence of an additional vortex nucleation mechanism, characterised by a critical velocity reduced by roton absorption, but ultimately determined by a requirement for the conservation of energy and momentum.

U2 - 10.1088/0022-3719/14/23/002

DO - 10.1088/0022-3719/14/23/002

M3 - Journal article

VL - 14

SP - L681-L686

JO - Journal of Physics C: Solid State Physics

JF - Journal of Physics C: Solid State Physics

SN - 0022-3719

ER -