No abstract available

No abstract available

[en] Rapid motion of the boundary of a plasma (through implosion or explosion, for instance) modifies (improves or degrades) both the electrostatic and loss cone confining properties. (author)

[en] We observe the toroidal field in the translated field reversed configuration (FRC) plasma although the FRC plasma has been thought to have the poloidal field only. We measured the toroidal field profile just after the plasma formation in order to make clear the location of the toroidal field self-occurrence. The remarkable field is observed in case of the plasma translation mode, but it is so small without active translation. The experimental result shows that the toroidal flux decays monotonically in time for the translation case. Then there may be no additive production during the translation process. (author)

[en] We give an equation describing the electric current stream-lines on the surface of a sphere that generates a magnetic field which contains a single multipole component. The equation shows how to wind a coil in order to produce a pure multipole field and helps to give an intuitive grasp of how well existing traps approximate multipoles. (Author)

[en] Invariant local surface equilibrium equations are derived that interrelate the absolute value of the magnetic field B, the absolute value of the gradient of the magnetic flux vertical bar ∇Φ vertical bar , the local shear s, and the plasma pressure on nested equilibrium magnetic surfaces in currentless configurations. Examples of applying these equations to analysis of symmetric and isodynamic equilibria are considered.

[en] Movies of edge turbulence at both the outboard midplane and the region outboard of the typical lower X-point location in C-Mod have been obtained using Gas-Puff-Imaging together with fast-framing cameras. Intermittent turbulent structures, typically referred to as blobs or filaments, are observed in both locations. Near the midplane the filaments are roughly circular in cross-section, while in the X-point region they are highly elongated. Filament velocities in this region are ∼3x faster than the radial velocities at the midplane, in a direction roughly normal to the local flux surfaces. The observations are consistent with the picture that the filaments arise in outboard region and, as a consequence of the rapid parallel diffusion of the potential perturbations, map along field lines. A simulation using the 3D BOUT turbulence code has been made, with the result that reproduces many of the spatial features observed in the experiment

No abstract available

No abstract available

[en] We studied, by micromagnetic numerical calculations, asymmetric vortex-core reversals driven by the m = −1 and m = +1 azimuthal spin-wave modes' excitations in soft magnetic circular nano-disks. We addressed the similarities and differences between the asymmetric core reversals in terms of the temporal evolutions of the correlated core-motion speed, locally concentrated perpendicular gyrofield, and magnetization dip near the original vortex core. The criterion for the core reversals was found to be the magnetization dip that must reach the out-of-plane magnetization component, m_z = −p, with the initial polarization p, where p = +1 (−1) for the upward (downward) core magnetization. The core-motion speed and the associated perpendicular gyrofield, variable and controllable with static perpendicular field, H_z, applied perpendicularly to the disk plane, must reach their threshold values to meet the ultimate core-reversal criterion. Also, we determined the H_z strength and direction dependence of the core-switching time and threshold exciting field strength required for the core reversals, whose parameters are essential in the application aspect. This work offers deeper insights into the azimuthal spin-wave-driven core-reversal dynamics as well as an efficient means of controlling the azimuthal-modes-driven core reversals