Search results for "Numerical approximation and analysis"

showing 2 items of 2 documents

Accretion shock on CTTSs and its X-ray emission

2009

High spectral resolution X-ray observations of classical T Tauri stars (CTTSs) demonstrate the presence of plasma at T~2-3×10^6 K and ne~10^11-10^13 cm-3. Stationary models suggest that this emission is due to shock-heated accreting material. We address this issue by a 1-D hydrodynamic model of the impact of the accretion flow onto a chromosphere of a CTTS with the aim of investigating the stability of accretion shock and the role of the chromosphere. Our simulations include the effects of gravity, radiative losses from optically thin plasma, the thermal conduction and a detailed modeling of the stellar chromosphere. Here we present the results of a simulation based on the parameters of the…

Shock wavePhysicsPlanetary bow shocksAstrophysics::High Energy Astrophysical Phenomenainterplanetary shocksPlasmaAstrophysicsNumerical approximation and analysisThermal conductionAccretion (astrophysics)T Tauri starSettore FIS/05 - Astronomia E AstrofisicaX-ray emission spectra and fluorescenceRadiative transferHydrodynamicsAstrophysics::Solar and Stellar AstrophysicsAstrophysics::Earth and Planetary AstrophysicsSpectral resolutionChromosphereAstrophysics::Galaxy Astrophysics
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Some considerations on the transmissivity of trirefringent metamaterials

2016

Nonlocal effects in metal–dielectric (MD) periodic nanostructures may typically be observed when the plasmonic particles and gaps are on the scale of a few tens of nanometers, enabling under certain conditions (succinctly for epsilon near zero) a collimated beam to split into three refracted signals. We developed a method for precisely evaluating the categorized transmissivity in an air/trirefringent metamaterial interface, which uses a fast one-dimensional Fourier transform and finite element solvers of Maxwell’s equations. In periodic arrays of MD nanofilms, it is proved a tunable transmissivity switch of the multirefracted beams under varying angle of incidence and wavelength, while keep…

Materials sciencePhysics::OpticsEffective medium theory02 engineering and technologyNumerical approximation and analysis01 natural sciencesCollimated light010309 opticsSplit-ring resonatorsymbols.namesakeOptics0103 physical sciencesPlasmonNanomaterialsÓpticabusiness.industryMetamaterialStatistical and Nonlinear Physics021001 nanoscience & nanotechnologyAtomic and Molecular Physics and OpticsFinite element methodWavelengthFourier transformAngle of incidence (optics)symbols0210 nano-technologybusiness
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