The conjecture that energy transport in sunspot penumbrae occurs through convection by an interchange of magnetic flux tubes is used in order to construct a magnetostatic model for a deep penumbra which is part of a global sunspot model. The model describes an overall mechanical equilibrium between the three stratifications: of the umbra, the penumbra, and of the solar convection zone, all of t...

The results of a numerical study an ordered substitution double-segment into the unit cell square artificial spin ice are presented. Each pattern vertex has three magnetic moment configurations that compete to form ground state in zero applied field, including nearest-neighbor and next-nearest-neighbor interaction contributions total magnetostatic energy. depends on number lattice sites conside...

For solid-state spin systems, the collective motion in a single crystal embodies multiple magnetostatic modes. Recently, it was found that cross-Kerr interaction between higher-order mode and Kittel introduces new operable degree of freedom. In this work, we propose scheme to entangle two magnon modes via nonlinearity when bias field is inhomogeneous system driven. Quantum entanglement persists...

We present a method for the generation of high kinetic energy attosecond electron packets via magnetostatic and aperture filtering of conical surface plasmon (SP) accelerated electrons. The conical SP waves are excited by coupling an ultrafast radially polarized laser beam to a conical silica lens coated with an Ag film. Electromagnetic and particle tracking models are employed to characterize ...

We devise an efficient algorithm for the finite element construction of discrete harmonic fields and the numerical solution of 3D magnetostatic problems. In particular, we construct a finite element basis of the first de Rham cohomology group of the computational domain. The proposed method works for general topological configurations and does not need the determination of “cutting” surfaces.