Electromagnetism

Electrostatics and electrodynamics underpin a wide range of experiments, measurements, devices, and theories. We use various computational techniques to study such systems, including photonics, magnonics and micromagnetics.

Figure: current density (cones) and electrostatic potential isolines (black).

For queries about this topic, contact Hans Fangohr.

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Projects

Ab initio simulations of chemical reactions on platinum nanoparticles

Chris-Kriton Skylaris (Investigator), Álvaro Ruiz-Serrano, Peter Cherry

•Use first principles calculations to study the relationship between shape and size of nanoparticle and the oxygen adsorption energy.

• Investigate the effect of high oxygen coverage on the catalytic activity of the nanoparticles.

All-Optical Phase Regeneration of Fiber Optic Communication Signals

Peter Horak (Investigator), Graham Hesketh

All-optical phase regeneration uses a process known as four-wave mixing in a nonlinear optical fiber to carefully mix light with a communication signal in such a way that it cancels transmission noise in the the signals phase, increasing the distance over which the signal can be transmitted. New regenerator designs are presented that suppress phase to amplitude noise conversion and performance is simulated using a supercomputer to assist experimental investigation.

Centre for Doctoral Training in Next Generation Computational Modelling

Hans Fangohr, Ian Hawke, Peter Horak (Investigators), Susanne Ufermann Fangohr, Thorsten Wittemeier, Kieran Selvon, Alvaro Perez-Diaz, David Lusher, Ashley Setter, Emanuele Zappia, Hossam Ragheb, Ryan Pepper, Stephen Gow, Jan Kamenik, Paul Chambers, Robert Entwistle, Rory Brown, Joshua Greenhalgh, James Harrison, Jonathon Waters, Ioannis Begleris, Craig Rafter

The £10million Centre for Doctoral Training was launched in November 2013 and is jointly funded by EPSRC, the University of Southampton, and its partners.

The NGCM brings together world-class simulation modelling research activities from across the University of Southampton and hosts a 4-year doctoral training programme that is the first of its kind in the UK.

Chaotic Analysis of Partial Discharge

Paul Lewin (Investigator), Lyuboslav Petrov

The deterministic character of PD pulses predicted by theory has been shown to be existent for certain PD events. Finding characteristic patterns in phase space enables field-data PD detection with high reliability.

Computational electromagnetic modelling of 3D photonic structures

Marc Molinari, Darren Bagnall, Simon Cox (Investigators), Asa Asadollahbaik, Elizabeth Hart

Nano-structured materials can provide very specific and often very special optical effects which can be exploited for a large range of optical applications including wavelength filters, LEDs, micro-lasers, HDTV, solar-cell coatings, optical high-Q fibres, diffraction gratings, polarisation devices, optical switches, etc. This research in “Computational Electromagnetic Modelling of 3D Photonic Structures” aims to address the need for accurate and fast three-dimensional modelling, simulation and analysis processes in the photonics industry. A FEM/FDTD software suite will be developed to simulate Maxwell’s field equations and thin-film quantum effects (plasmons) in the visible and near-infrared EM frequency spectrum. The results obtained from running the software on suitable compute clusters will then be compared to the analysis results of experimentally manufactured materials. We will investigate structures occurring in nature such as iridescent butterfly wings, white/black reflecting beetle shells, etc., and aim to optimise artificially designed structures with periodic, quasi-periodic and random configurations.

Directing magnetic skyrmion traffic flow with nanoscale patterning.

Hans Fangohr (Investigator), Mark Vousden

Skyrmions in magnetic nanostructures may lead to new data storage technologies. Appropriate simulation methodologies are developed and applied.

Dynamics of interacting magnetic nanoparticles

Thomas Fischbacher (Investigator), Maximilian Albert

The project aims at extending the micromagnetic simulation framework 'nmag' developed at the University of Southampton to enable it to handle dynamic geometries. The extended framework will then be used to study systems such as interacting magnetic nanoparticles.

Efficient algorithms for liquid crystal alignment

Giampaolo D'Alessandro, Timothy Sluckin (Investigators)

We have developed an efficient algorithm to determine the liquid crystal alignment in the absence of defects. The aim of this project is to extend this algorithm to include defects.

Investigation into the Interfacial Physics of Field Effect Biosensors

Nicolas Green, Chris-Kriton Skylaris (Investigators), Benjamin Lowe

This interdisciplinary research aims to improve understanding of Field Effect Transistor Biosensors (Bio-FETs) and to work towards a multiscale model which can be used to better understand and predict device response.

Modelling the Combined Effects of Total Ionizing Dose and Random Dopant Fluctuations in sub-100 nm gate-length Transistors

Kees de Groot (Investigator), Eleni Chatzikyriakou

The radiation hardness of state-of-the-art silicon-on-insulator transistors of gate length dimensions of 90 nm and beyond is investigated. The combined effects of oxide charges and random fluctuations of the dopant atoms in silicon are considered. It is demonstrated that a parasitic channel forms at the interface of buried oxide and shallow trench isolation regions of the device and that this effect is aggravated by random dopant fluctuations.

Multimode simulation of high power fibre lasers and amplifiers

Peter Horak (Investigator), Ioannis Begleris

This project aims to address the challenge of ever-increasing demand for higher powers from fibre lasers by developing theoretical and numerical methods to simulate laser pulse amplification in large-mode area fibres supporting multiple spatial modes.

On the applicability of nonlinear timeseries methods for partial discharge analysis

Paul Lewin (Investigator), Lyuboslav Petrov

The governing processes of Partial Discharge (PD)
phenomena trigger aperiodic chains of events resulting in ’ap-
parently’ stochastic data, for which the widely adopted analysis
methodology is of statistical nature. However, it can be shown,
that nonlinear analysis methods can prove more adequate in
detecting certain trends and patterns in complex PD timeseries.
In this work, the application of nonlinear invariants and phase
space methods for PD analysis are discussed and potential pitfalls
are identified. Unsupervised statistical inference techniques based
on the use of surrogate data sets are proposed and employed for
the purpose of testing the applicability of nonlinear algorithms
and methods. The Generalized Hurst Exponent and Lempel Ziv
Complexity are used for finding the location of the system under
test on the spectrum between determinism and stochasticity. The
algorithms are found to have strong classification abilities at
discerning between surrogates and original point series, giving
motivation for further investigations.

Optical Characterisation of Black Silicon for Photovoltaics Using the Finite Element Method

Jack Tyson (Investigator)

Here we present a novel method of simulating the reflectance spectra of black silicon solar cells using the finite element method. Designed in COMSOL Multiphysics is a new set of algorithm-controlled-geometries rendering a vast array of different structural permutations of silicon nanowires. Our model focused on the variation of this geometry within customisable predefined conditions in large output quantities, collated and averaged to reliably determine the reflectance of an entire black silicon solar cell.