A. S. Malishevskii

4π-kink vortices in long Josephson junctions

Abstract The analytic theory of 4π-kinks in long Josephson junctions is presented. The laws for the velocity “quantized” spectrum of the different modes of the moving 4π-kinks nonlinear vortices are obtained. The discreteness of the velocity spectrum is dictated by the condition of the phase matching of the nonlinear state which does not permit breaking of the vortices due to the Cherenkov radiation.

Fast Josephson vortex

Abstract For the magnetically coupled waveguide and long Josephson junction we gave the analytic description of two separate velocity domains where the free motion of traveling vortex (2 π -kink) exists. The role of the mutual influence of waveguide and long Josephson junction is discussed. It is shown the possibility of the fast vortex motion with the velocity much larger than Swihart velocity of Josephson junction and close to the speed of light in the waveguide. The excitation of motion of such fast Josephson vortex is described.

Gluing of Josephson vortices by Cherenkov-trapped Swihart waves

A theory of Josephson vortices-multikinks moving with a constant velocity is formulated for non-dissipative Josephson junctions on the basis of the Aubry-Volkov analytical model. Cherenkov trapping of Swihart waves by moving vortices is predicted. A description of the structure of vortices which is due to the waves trapped by them is given. It is predicted that the characteristic velocities of the moving vortices are discrete. This phenomenon is due to the structure of the Swihart waves trapped by the vortices. The concept of gluing of elementary Josephson vortices by Swihart waves in a coherently-phased, multivortex, structure is advanced.

Properties of a fast Josephson vortex

A model is formulated for the analytic description of vortices in a system consisting of a long Josephson junction (JJ) and a waveguide that is magnetically coupled to this junction. The application of this model made it possible to determine the allowed range of velocities of a vortex. It is established that a free vortex can move with a velocity much greater than the Swihart velocity of a Josephson junction. Such a vortex is called fast. The effect of the waveguide on the forced motion of vortices is studied. It is shown that fast vortices can be generated at relatively small values of current.

10π-kink and conception of Cherenkov gluing of the Josephson vortices

Abstract Within the Aubry–Volkov approach, when relationship of Josephson current density with the phase difference of Cooper pair wave functions has saw-like type, the description of structure and discrete spectrum of velocities of travelling 10π-kink is given. The dependence of discrete spectrum of velocity eigenvalues on a set of two numbers defining the number of Swihart wavelengths trapped by vortex is obtained. It is shown how five separate 2π-kinks are glued by trapped Swihart waves into unified 10π-kink.

On the decay of generalized Swihart waves

For Josephson junctions in sandwich geometry and in thin-film geometry we formulate the equations of nonlocal electrodynamics which take account of the influence of normal electrons in superconductors. On the basis of these equations we examine the spectrum and decay of generalized Swihart waves. We find that the decay of these waves by normal electrons becomes especially prominent in the short-wavelength region. Comparison of various dissipation mechanisms has revealed the conditions for efficient emission of electromagnetic waves from Josephson structures with finite dimensions.

Cherenkov trapping of waves and discreteness of 6 π-kink motion in a long Josephson junction

The phenomenon of Cherenkov trapping of generalized Swihart waves by a moving vortex is established using an analytically solvable model. The quantization of the structure of the field of the trapped waves is manifested as quantization of the values of the velocity of the vortices.

A Chain of Fast Vortices and the Current–Voltage Characteristic of an Annular Josephson Junction

It is demonstrated that a chain of fast vortices produces a peak in the current–voltage characteristic of an annular Josephson junction coupled to a waveguide.

Cherenkov radiation linewidth of a Josephson vortex train

The widths of Cherenkov radiation spectrum lines of Josephson vortex trains in extended sandwiches are determined. Conditions are determined such that the line widths owing to a finite train length are comparable to or less than the line widths owing to thermal fluctuations.

Terahertz radiation from Josephson sandwiches

Basic results are presented from a study of the Cerenkov emission of electromagnetic waves by solitary vortices and Swihart waves moving in a long Josephson sandwich embedded in a dielectric. The energy fluxes of the electromagnetic field along a long sandwich are examined. The magnitudes of the fluxes are compared over a wide range of frequencies and wave numbers of surface waves in the sandwich.