Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

ION TRANSPORT AT INTERMEDIATE FIELDS AT LOW PRESSURE

A. F. Borghesani

Published May 31, 2007• 0 citations
Publisher

Abstract

Abstract At higher electric fields, the drifting ions are not in thermal equilibrium with the gas of the elementary excitations of the superfluid, and the mobility depends on the field. This chapter presents the experimental results of the ion mobility in the superfluid at higher fields and larger temperatures. The field dependence of the mobility is explained in terms of roton scattering in presence of an enhanced roton density around the charge. Emphasis is given on the discovery of the giant mobility discontinuity at which the excess energy is dissipated by ions creating quantized vortex rings. Ions are captured by them and drift together as a new, single unit called a charged vortex ring. The puzzling issue of the drift velocity discontinuities is also addressed.

DOI
10.1093/acprof:oso/9780199213603.003.0006

Related papers

BARE-ION TRANSPORT AT HIGH FIELDS

A. F. Borghesani

Abstract This chapter describes the phenomena observed when the drift field is large enough for ions to escape capture by vortex rings. The electric field dependence of the ion drift velocity at high fields can be interpreted in terms of a sequence of trapping and detrapping events. At very high field, ions can drift without being captured by vortex rings, and eventually they may reach velocities in excess of the Landau critical velocity for roton emission. The breaking of the roton barrier is described in great detail because of its importance. It is the first time that a macroscopic critical velocity has been reached in the superfluid by a moving object. The microscopic size of the ions has allowed this impressive goal to be reached.

•May 31, 2007•0 citations

Ion Motion in Dilute He3 - He4 Solutions at Ultralow Temperatures

Moyses Kuchnir, John B. Ketterson, Pat R. Roach

Measurements of the velocity of charge carriers in several dilute solutions of $^{3}\mathrm{He}$ in $^{4}\mathrm{He}$ in the temperature range 0.017-1.0 K are reported. The low-field negative-ion mobility shows a ${T}^{\ensuremath{-}\frac{1}{2}}$ dependence below 0.08 K characteristic of hard-sphere scattering. A maximum is observed in the mobility in the vicinity of 0.4 K. This can be interpreted in terms of a $^{3}\mathrm{He}$ condensation on the bubble surface. The positive-ion mobility is nearly temperature independent below 0.7 K. This has recently been interpreted in terms of a momentum-dependent polarization scattering. The field dependence of the positive-carrier velocity shows a discontinuity in the vortex-ring regime. The discontinuity can be shown to result from a size-dependent drag coefficient and a maximum is observed for very small rings (\ensuremath{\sim}16 \AA{}).

Physical Review A•Jul 1, 1972•67 citations

MOBILITY OF ION IN A SYSTEM OF INTERACTING BOSE PARTICLES. Technical Report No. 5

Ryo Abe, Ko Aizu

The transport property of an ion in a dilute Bose-Einstein gas subject to an external electric field is investigated through Boltzmann equation approach. By means of the Bogolyubov transformation, the interaction hamiltonian between ion and elementary excitation is obtained, and the cross section for the scattering of the ion from phonons or rotons is calculated. The solution to the Boltzmann equation is obtained by the use of a variation principle, and the temperature dependence of ion mobility is shown to be UPSILON /sup -4/ at very low temperature regions where phonon excitations are more important than rotons. At higher temperatures where roton excitations are important the temperature dependence is shown to be UPSILON /sup -1/ exp( DELTA /k UPSILON ), where DELTA is the excitation energy of roton. The agreement in absolute magnitude with the experimental data in liquid helium is obtained by choosing reasonable value of parameter both in higher and lower temperature regions. Comparison with the Khalatnikov and Zharkov theory is given, and also the ion mobility in Fermi system is briefly discussed. (auth)

•Jan 1, 1960•0 citations

Mobility of Negative Ions Along Vortices in Rotating Superfluid Helium

Roger L. Douglass

The mobility of negative ions trapped on linear vortices in rotating superfluid helium has been measured by a time-of-flight technique in the temperature range $0.8\ifmmode^\circ\else\textdegree\fi{}\mathrm{K}<T<1.6\ifmmode^\circ\else\textdegree\fi{}\mathrm{K}$. Measurements could not be extended below 0.8\ifmmode^\circ\else\textdegree\fi{}K because, contrary to the present theory, the ion escape rate became too large. No evidence of direct trapping of positive ions by vortex lines was observed down to 0.4\ifmmode^\circ\else\textdegree\fi{}K. The trapped-ion mobility is interpreted in terms of scattering of the ion by thermal distributions of quantized vortex waves and rotons localized about the vortex axis.

Physical Review•Oct 5, 1968•56 citations

Motion of Ions Trapped on Vortices in He II

Richard M. Ostermeier, William I. Glaberson

We have measured the drift velocity of ions trapped on vortex lines at temperatures down to 0.35 K. We observe several effects which cannot easily be explained in terms of existing theories, including the broadening of an ion pulse, a limiting velocity in high electric fields, and a zero-field mobility which increases, at lower temperatures, much more rapidly than expected. An attempt is made to explain qualitatively some of these effects.

Physical Review Letters•Jul 28, 1975•47 citations

Vortex nucleation limited mobility of free electron bubbles in the Gross-Pitaevskii model of a superfluid

Alberto Villois, Hayder Salman

We study the motion of an electron bubble in the zero-temperature limit where neither phonons nor rotons provide a significant contribution to the drag exerted on an ion moving within the superfluid. By using the Gross-Clark model, in which a Gross-Pitaevskii equation for the superfluid wave function is coupled to a Schr\"odinger equation for the electron wave function, we study how vortex nucleation affects the measured drift velocity of the ion. We use parameters that give realistic values of the ratio of the radius of the bubble with respect to the healing length in superfluid $^{4}\mathrm{He}$ at a pressure of one bar. By performing fully three-dimensional spatiotemporal simulations of the superfluid coupled to an electron, that is modeled within an adiabatic approximation and moving under the influence of an applied electric field, we are able to recover the key dynamics of the ion-vortex interactions that arise and the subsequent ion-vortex complexes that can form. Using the numerically computed drift velocity of the ion as a function of the applied electric field, we determine the vortex nucleation limited mobility of the ion to recover values in good agreement with measured data.

arXiv:1708.06154•Physical review. B./Physical review. B•Mar 13, 2018•15 citations
Abstract At higher electric fields, the drifting ions are not in thermal equilibrium with the gas of the elementary excitations of the superfluid, and the mobility depends on the field. This chapter presents the experimental results of the ion mobility in the superfluid at higher fields and larger temperatures. The field dependence of the mobility is explained in terms of roton scattering in presence of an enhanced roton density around the charge. Emphasis is given on the discovery of the giant mobility discontinuity at which the excess energy is dissipated by ions creating quantized vortex rings. Ions are captured by them and drift together as a new, single unit called a charged vortex ring. The puzzling issue of the drift velocity discontinuities is also addressed.
Abstract This chapter describes the phenomena observed when the drift field is large enough for ions to escape capture by vortex rings. The electric field dependence of the ion drift velocity at high fields can be interpreted in terms of a sequence of trapping and detrapping events. At very high field, ions can drift without being captured by vortex rings, and eventually they may reach velocities in excess of the Landau critical velocity for roton emission. The breaking of the roton barrier is described in great detail because of its importance. It is the first time that a macroscopic critical velocity has been reached in the superfluid by a moving object. The microscopic size of the ions has allowed this impressive goal to be reached.
Measurements of the velocity of charge carriers in several dilute solutions of 3He^{3}\mathrm{He}3He in 4He^{4}\mathrm{He}4He in the temperature range 0.017-1.0 K are reported. The low-field negative-ion mobility shows a ${T}^{\ensuremath{-}\frac{1}{2}}$ dependence below 0.08 K characteristic of hard-sphere scattering. A maximum is observed in the mobility in the vicinity of 0.4 K. This can be interpreted in terms of a 3He^{3}\mathrm{He}3He condensation on the bubble surface. The positive-ion mobility is nearly temperature independent below 0.7 K. This has recently been interpreted in terms of a momentum-dependent polarization scattering. The field dependence of the positive-carrier velocity shows a discontinuity in the vortex-ring regime. The discontinuity can be shown to result from a size-dependent drag coefficient and a maximum is observed for very small rings (\ensuremath{\sim}16 \AA{}).
The transport property of an ion in a dilute Bose-Einstein gas subject to an external electric field is investigated through Boltzmann equation approach. By means of the Bogolyubov transformation, the interaction hamiltonian between ion and elementary excitation is obtained, and the cross section for the scattering of the ion from phonons or rotons is calculated. The solution to the Boltzmann equation is obtained by the use of a variation principle, and the temperature dependence of ion mobility is shown to be UPSILON /sup -4/ at very low temperature regions where phonon excitations are more important than rotons. At higher temperatures where roton excitations are important the temperature dependence is shown to be UPSILON /sup -1/ exp( DELTA /k UPSILON ), where DELTA is the excitation energy of roton. The agreement in absolute magnitude with the experimental data in liquid helium is obtained by choosing reasonable value of parameter both in higher and lower temperature regions. Comparison with the Khalatnikov and Zharkov theory is given, and also the ion mobility in Fermi system is briefly discussed. (auth)
The mobility of negative ions trapped on linear vortices in rotating superfluid helium has been measured by a time-of-flight technique in the temperature range $0.8\ifmmode^\circ\else\textdegree\fi{}\mathrm{K}<T<1.6\ifmmode^\circ\else\textdegree\fi{}\mathrm{K}$. Measurements could not be extended below 0.8\ifmmode^\circ\else\textdegree\fi{}K because, contrary to the present theory, the ion escape rate became too large. No evidence of direct trapping of positive ions by vortex lines was observed down to 0.4\ifmmode^\circ\else\textdegree\fi{}K. The trapped-ion mobility is interpreted in terms of scattering of the ion by thermal distributions of quantized vortex waves and rotons localized about the vortex axis.
We study the motion of an electron bubble in the zero-temperature limit where neither phonons nor rotons provide a significant contribution to the drag exerted on an ion moving within the superfluid. By using the Gross-Clark model, in which a Gross-Pitaevskii equation for the superfluid wave function is coupled to a Schr\"odinger equation for the electron wave function, we study how vortex nucleation affects the measured drift velocity of the ion. We use parameters that give realistic values of the ratio of the radius of the bubble with respect to the healing length in superfluid 4He^{4}\mathrm{He}4He at a pressure of one bar. By performing fully three-dimensional spatiotemporal simulations of the superfluid coupled to an electron, that is modeled within an adiabatic approximation and moving under the influence of an applied electric field, we are able to recover the key dynamics of the ion-vortex interactions that arise and the subsequent ion-vortex complexes that can form. Using the numerically computed drift velocity of the ion as a function of the applied electric field, we determine the vortex nucleation limited mobility of the ion to recover values in good agreement with measured data.