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Upcoming events in Mathematics

(previous see here)
Mon 24/09/18 15:00
EduZone@Library
Mathematics Seminar
Dr. David MacTaggart (University of Glasgow)
The non-modal onset of the tearing instability
abstract

Abstract

I will discuss the onset of the classical magnetohydrodynamic (MHD) tearing instability (TI) and focus on non-modal (transient) growth rather than the tearing mode. With the help of pseudospectral theory, I will demonstrate that the operators of the linear equations are highly non-normal, resulting in the possibility of significant transient growth at the onset of the TI. This possibility increases as the Lundquist number S increases. In particular, I will show evidence that the maximum possible transient growth, measured in the L2-norm, for the classical setup of current sheets unstable to the TI, scales as O(S1/4) on time scales of O(S1/4) for S≫1. This behaviour is much faster than the time scale O(S1/2) when the solution behaviour is dominated by the tearing mode. The size of transient growth obtained is dependent on the form of the initial perturbation. I will decribe the form of the optimal initial conditions for the maximum possible transient growth. Further, I will examine how the structure of the eigenvalue spectrum relates to physical quantities.

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Mon 01/10/18 15:00
Dalhousie 1G05
Mathematics Seminar
Dr. Maria Lopez-Fernandez (Universita di Roma)
Variable time-stepping approximation of convolution equations arising in wave scattering problems
abstract

Abstract

I will present the generalized Convolution Quadratures (gCQ) for the numerical approximation of convolution equations arising in wave scattering problems. The gCQ is a family of time-stepping procedures which allows to use variable steps, possibly driven by some error control mechanism. The derivation of the gCQ is accomplished by working in the Laplace domain and its implementation relies on contour integral techniques in the complex plane. Numerical experiments are presented to show the potential of our approach.

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Mon 08/10/18 15:00
EduZone@Library
Mathematics Seminar
Dr. Tristan Pryer (University of Reading)
(Themes: Numerical Analysis)
Mon 15/10/18 15:00
Fulton H2
Mathematics Seminar
Dr. Nikos Katzourakis (University of Reading)
(Themes: Partial Differential Equations)
Mon 12/11/18 15:00
EduZone@Library
Mathematics Seminar
Prof. Nicola Bellomo (Politecnico di Torino)
(Themes: Crowds and Swarm dynamics)
Mon 19/11/18 15:00
EduZone@Library
Mathematics Seminar
Dr. Rui Travasso (Centro de Fisica Computacional, University of Coimbra)
(Themes: Mathematical Biology)