Spin-torque oscillators based on a single MTJ with in-plane magnetization [1] exhibit high frequency capabilities, but still need an external biasing magnetic field and are characterized by low output power level [2]. Oscillators on MTJs with perpendicular magnetization [3] and vortex-based oscillators [4] are shown to generate oscillations without external magnetic field, however, their low op...

The equations of magnetohydrostatic equilibria for a plasma in a gravitational field are investigated analytically. For equilibria with one ignorable spatial coordinate, these equations reduce to a single nonlinear elliptic equation for the magnetic vector potential A. This equation depends on an arbitrary function of A that must be specified. In this paper analytical nonlinear periodic solutio...

We present numerical 2D magnetostatic models for sunspot penumbrae consisting of radially aligned field-free gaps in a potential magnetic field, as proposed by Spruit and Scharmer (2006). The shape of the gaps and the field configurations around them are computed consistently from the condition of magnetostatic pressure balance between the gap and the magnetic field. The results show that field...

We develop an effective low-frequency theory of the electromagnetic field in equilibrium with thermal objects. The aim is to compute thermal magnetic noise spectra close to metallic microstructures. We focus on the limit where the material response is characterized by the electric conductivity. At the boundary between empty space and metallic microstructures, a large jump occurs in the dielectr...