Browsing by Author "Du, Q."

Now showing 1 - 3 of 3
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    Computational simulation of type-II superconductivity including pinning phenomena
    Du, Q.; Gunzburger, Max D.; Peterson, Janet S. (American Physical Society, 1995-06-15)
    A flexible tool, based on the finite-element method, for the computational simulation of vortex phenomena in type-II superconductors has been developed. These simulations use refined or newly developed phenomenological models including a time-dependent Ginzburg-Landau model, a variable-thickness thin-film model, simplified models valid for high values of the Ginzburg-Landau parameter, models that account for normal inclusions and Josephson effects, and the Lawrence-Doniach model for layered superconductors. Here, sample results are provided for the case of constant applied magnetic fields. Included in the results are cases of flux pinning by impurities and by thin regions in films.
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    Solving the Ginzburg-Landau equations by finite-element methods
    Du, Q.; Gunzburger, Max D.; Peterson, Janet S. (American Physical Society, 1992-10)
    We consider finite-element methods for the approximation of solutions of the Ginzburg-Landau equations of superconductivity. The methods are based on a discretization of the Euler-Lagrange equations resulting from the minimization of the free-energy functional. The discretization is effected by requiring the approximate solution to be a piecewise polynomial with respect to a grid. The magnetization versus magnetic field curves obtained through the finite-element methods agree well with analogous calculations obtained by other schemes. We demonstrate, both by analyzing the algorithms and through computational experiments, that finite-element methods can be very effective and efficient means for the computational simulation of superconductivity phenomena and therefore could be applied to determine macroscopic properties of inhomogeneous, anisotropic superconductors.
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    Stochastic dynamics of Ginzburg-Landau vortices in superconductors
    Deang, Jennifer M.; Du, Q.; Gunzburger, Max D. (American Physical Society, 2001-08-01)
    Thermal fluctuations and randomly distributed defects in superconductors are modeled by stochastic variants of the time-dependent Ginzburg-Landau equations. Numerical simulations are used to compare the effects of additive and multiplicative noise models.