Related papers: The Analysis of Penumbral Fine Structure Using an …
We demonstrate analytically and numerically that a subwavelength-core dielectric photonic nanowire embedded in a properly designed photonic crystal fiber cladding shows evidence of a previously unknown kind of nonlinearity (the magnitude of…
A theory of the nonlinear plasma waves in graphene is developed in the nonperturbative regime. The influence of strong electric fields on the position and linewidth of plasma resonances in the far-infrared transmission experiments, as well…
Observations of the Sun in the visible spectral range belong to standard measurements obtained by instruments both on the ground and in the space. Nowadays, both nearly continuous full-disc observations with medium resolution and dedicated…
The specificity of modal-expansion formalisms is their capabilities to model the physical properties in the natural resonance-state basis of the system in question, leading to a transparent interpretation of the numerical results. In…
Active regions often host large-scale gas flows in the chromosphere presumably directed along curved magnetic field lines. Spectropolarimetric observations of these flows are critical to understanding the nature and evolution of their…
In this paper we employ the emerging paradigm of physics-informed neural networks (PINNs) for the solution of representative inverse scattering problems in photonic metamaterials and nano-optics technologies. In particular, we successfully…
Sunspots are prominent manifestations of the solar cycle and provide key constraints for understanding its operation. Also, knowing internal structure of sunspots allows us to gain insights on the energy transport in strong magnetic fields…
The inverse problem of electrical impedance tomography is severely ill-posed, meaning that, only limited information about the conductivity can in practice be recovered from boundary measurements of electric current and voltage. Recently it…
Indentation test is used with growing popularity for the characterization of various materials on different scales. Developed methods are combining the test with computer simulation and inverse analyses to assess material parameters…
Context: Observations at 0.1" have revealed the existence of dark cores in the bright filaments of sunspot penumbrae. Expectations are high that such dark-cored filaments are the basic building blocks of the penumbra, but their nature…
Prominences show a surprising amount of fine structure and it is widely believed that their threads, as seen in H$\alpha$ observations, provide indirect information concerning magnetic field topology. We investigate the spontaneous…
Accurate emission line fluxes from planetary nebulae (PNe) provide important constraints on the nature of the final phases of stellar evolution. Large, evolved PNe may trace the latest stages of PN evolution, where material from the AGB…
Sunspots are concentrations of magnetic field on the visible solar surface that strongly affect the convective energy transport in their interior and surroundings. The filamentary outer regions (penumbrae) of sunspots show systematic radial…
This paper investigates model-order reduction methods for geometrically nonlinear structures. The parametrisation method of invariant manifolds is used and adapted to the case of mechanical systems expressed in the physical basis, so that…
We introduce a methodology to test models with spatial variations of the fine-structure constant $\alpha$, based on the calculation of the angular power spectrum of these measurements. This methodology enables comparisons of observations…
Many properties of photonic structures rely on band topology characterized by the integer invariants that can change during the topological transitions and give rise to the disorder-robust topological edge, corner, or interface states.…
We analyze spectropolarimetric data taken with the Hinode spacecraft in quiet solar regions at the disk center. Distorted redshifted Stokes $V$ profiles are found showing a characteristic evolution that always follows the same sequence of…
This paper studies the inverse problem related to the identification of the flexural stiffness of an Euler Bernoulli beam in order to reconstruct its profile starting from available response data. The proposed identification procedure makes…
We apply a rigorous eigenmode analysis to study the electromagnetic properties of linear and weakly nonlinear metamaterials. The nonlinear response can be totally described by the linear eigenmodes when weak nonlinearities are attributed to…
I deduced a 3-D sunspot model that is in agreement with spectropolarimetric observations, to address the question of penumbral heating by the repetitive rise of flow channels. I performed inversions of data taken simultaneously in infrared…