[en] The problem of constructing flux coordinates for a tokamak is discussed. Different coordinate systems are considered using a unified approach. The problem is formulated in terms of two magnetic differential equations with known right-hand sides. The construction of tokamak flux coordinates with straightened field lines reduces to the problem of calculating one or two integrals around a poloidal contour on a magnetic surface. Three coordinate systems are analyzed, specifically, coordinates with a prescribed toroidal angle and Hamada and Boozer coordinates. It is shown how one coordinate system can be transformed into another and how the required calculations can be performed without a complete change of variables. The results obtained are intended to be used in practical manipulations with flux coordinates

[en] Three-dimensional magnetic structures of pi-vertical-Bloch line (VBL) and 2pi-VBL are investigated in 80 - 320-nm-thick Permalloy films using direct integration of the Landau - Lifshitz - Gilbert equation in an 128x128x80 point Cartesian lattice. A pi-VBL reflects the shapes of its adjacent walls, which change with film thickness. The pi-VBL conducts the flux between walls of opposite chirality by letting the magnetization rotate out of the plane of the walls via a vortex structure. The Neel caps switch chirality via a 'converging point,' or cross-tie, flux at one surface and a vortex flux, or a swirl, at the other surface. The pi-VBL energy per unit area is 0.44, 0.20, and 0.30 erg/cm2 in 80, 160, and 320 nm films, respectively. The corresponding pi-VBL widths are 88, 60, and 86 nm. A stable winding 2pi-VBL structure was also computed by combining two pi-VBL structures of appropriate chirality. The Neel caps intersect via the pair-(swirl, converging point) like flux at both surfaces. The width of the 2pi-VBL is 140 nm and its energy per unit area is 0.57 erg/cm2. [copyright] 2001 American Institute of Physics

[en] A problem of constructing the flux coordinates for a tokamak is discussed. The problem is formulated in the form of two magnetic differential equations with a known right part. The construction of the flux coordinates with straightened force lines for a tokamak is reduced to calculation of one or three contour integrals in the cross section of a magnetic surface. Three versions of the flux coordinates are considered. A technique for transition from one coordinates to other ones is described

No abstract available

[en] The method to construct the generalized magnetic coordinate system is presented, which describe the magnetic field with and without magnetic surfaces. The method is applied to a simple analytic field. (author)

No abstract available

[en] Effective method is proposed to construct the flux coordinates for toroidal plasma equilibrium configurations. This method is applied to conventional stellarators. Three kinds of flux coordinates are considered: coordinates with a fixed toroidal angle, Hamada and Boozer coordinates. (author)

[en] We have studied fluxoid quantization effects in mesoscopic Al samples consisting of a small number of square loops. In short microladders a pronounced substructure of the Little-Parks oscillations (i.e. the oscillations of the critical temperature T_c as a function of the applied magnetic flux φ) has been found. These new features in T_c(φ) originate from transitions between different quantum states, each having a specific order parameter profile and flow pattern of the supercurrents. The experimental data are in excellent agreement with the T_c(φ) calculated within the de Gennes-Alexander model for superconducting micronetworks. (orig.)

[en] An outer magnetic field may penetrate superconducting material in form of quantised flux tubes. It they are pinned to defects in the material the superconductor can carry electric power without loss. Power carrying capcities are limited because flux lines may depin because of their temperature fluctuation. (orig.)

No abstract available