Response to comments on the article “Electric properties of metallic nanowires obtained in quantum vortices of superfluid helium,” by E. B. Gordon, A. V. Karabulin, V. I. Matyushenko, V. D. Sizov, and I. I. Khodos, Fiz. Nizk. Temp. 36, 740 (2010) [Low Temp. Phys. 36, 590 (2010)]

Metallic nanowires and mesoscopic networks on a free surface of superfluid helium and charge-shuttling across the liquid–gas interface

“…The minimum of the particle velocity obtained in the experiment falls well within the range of low Reynolds number for the whole range of the electric field strength. It is therefore unlikely that the discrepancy arises because of the usage of eqn (11). We therefore suggest that some of the longer nanowires in contact with the electrode do not acquire the maximum charge as given by eqn (8) and therefore move slower than expected.…”

“…Second, nanowires were formed also in normal fluid He, at a temperature above 2.17 K. However, in that case no larger structures, such as networks and millimeter-long filaments could be observed and the nanowires had a less smooth structure. 20 In the present work we investigate the formation of nanowires, filaments and networks in a system that represents a two-dimensional trap for impurity particles, as opposed to a one-dimensional trap produced by a quantized vortex. The trapping potential is created by a combination of a vertical static electric field and a horizontal free surface of superfluid He.…”

“…21,22 More recently, the diffusion of neutral impurity particles in liquid He and their coalescence into small clusters has been analyzed. 17,20 However, a detailed theory of a nanowire or a filament growth on the superfluid He vortex does not yet exist. Especially puzzling is the advanced stage of the filament formation process, when the individual nanowires become entangled and twisted together to form millimeter-sized ''ropes'' and networks.…”

“…18 Their ability to attract and trap small particles is well known since the pioneering work 19 on the trapping of free electrons in 1970-ies. It was therefore suggested that in superfluid He both, hydrogen filaments 3,5 and metallic nanowires 6,7 are formed due to the aggregation of dopants trapped at the vortex core. Currently, most publications on this quickly growing field of research support that interpretation, 10,[14][15][16]20 both for bulk superfluid He and for He microdroplets.…”

On charged impurity structures in liquid helium

“…Such particles and systems have found many different applications: visualization of flows and quantum vortices in superfluid helium [2][3][4]; study of energy transfer phenomena in liquid helium [5]; development of new high-energy density materials [6][7][8]; investigation of tunneling reactions of hydrogen isotopes in impurity-helium condensates [9]; structural studies of rare gas, molecular deuterium and nitrogen nanoclusters [10][11][12]; study of cold neutron interaction with watergels [13,14]; synthesis of metallic nanowires in superfluid helium [15,16]. Laser ablation of metallic target in solid helium-4 allows to create so-called icebergs (helium crystals doped with metallic particles) remaining metastable below the melting curve [17,18].…”