Seminarios de física del mes de junio

Dr. Viktor Fedun
(Department of Automatic Control and Systems Engineering, University of Sheffield) 

Title: 3D numerical modeling of MHD wave propagation in realistic solar magnetic configurations
 
Abstract: The Suns outer atmosphere is riddled with complex magnetic fields and explosive plasma processes, which evolve across spatial scales comparable with the size of the Earth. The theory that describes this extreme environment is Magneto-HydroDynamics (MHD) and solving the governing equations in 3D makes this a computationally intensive challenge. Sheffield Advanced Code (SAC) is a magnetohydrodynamic (MHD) code with the capacity to simulate the interaction of any arbitrary perturbation (i.e., not necessarily limited to the linearised limit) with a magnetohydrostatic equilibrium background. This code is build on the base of the well-known Versatile Advection Code (VAC; Tóth 1996). The governing equations are implemented in a novel way. Sub-grid diffusion and resistivity are applied to ensure numerical stability of the computed solution of the MHD equations. We apply a fourth-order central difference scheme to calculate the spatial derivatives, and implement a Runge-Kutta scheme to advance the solution in time. Also, I will discuss recently developed analytical model of realistic magnetic field configurations which are typical for the lower solar atmosphere. Systems incorporating open single and multiple flux tubes and closed magnetic loops can be combined to form magnetic structures that could even represent complex solar active regions. This model successfully spans the Interface region of the solar atmosphere, from the photosphere up to the solar corona across the challenging transition region, while retaining physically valid plasma pressure, density and magnetic flux. Modelling magnetic structures can depict the main characteristics of solar intergranular lanes or active regions.

Fecha: Viernes, 24 de Junio de 2016
Hora: 12:00 Hrs
Lugar: Salon 2, Edificio C3, IFM-UMSNH

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