UpComing Seminars Recent Seminars | Dr Antonio Lei
On the Finiteness of Selmer groups Dr Byoung Du Kin
The congruences of congruent modular forms for non-ordinary primes
Dr Ernesto Nungesser
The future of some homogeneous spacetimes with an ensemble of free falling particles Professor Alan Coley
Persistence of black holes through
a cosmological bounce
Prof. Heiko Knospe
Nonstandard methods in p-adic analysis
Patrick Noble
A Bayesian Method for Forecasting Solar Cycles Using a Fokker-Planck Equation Woei Chet Lim
BKL singularity, spikes and inhomogeneous cosmology Emeritus Prof. R. Delbourgo
The big physics questions –
Some answers
Dr Daniel Delbourgo
How fast do solutions to polynomial equations grow?
Lyndon Embling (MSc student)
Axiomitisations of some Quasi-Ordered
Functions Semigroups using Determinative Pairs
Craig Armstrong (PhD student)
Modeling solar loop-top electron transport
using stochastic methods
Professor Geoffrey Grimmett - 2012 FORDER LECTURER
Conformality and universality in probability
Juri Toomre
Touching the inside of a convecting star and its magnetic dynamo Professor Florian Luca
Sierpinski and Riesel numbers and their friends
Dr Nick Cavenagh
A comparative study of defining sets in designs
Assoc. Prof. Steven Galbraith
Euclid's algorithm, continued fractions, factoring and the approximate GCD problem Dr Peter Kritzer
Uniformly Distributed Point Sets and Their Application to Quasi-Monte Carlo Algorithms
Dr Marcel Jackson
Constraint Satisfaction Problems and Universal Algebra
Dr Timothy Stokes
Comparison Semigroups and Function Algebra
Professor Ben Green
Arithmetic progressions of primes
Professor Ben Green
Linear equations in primes
Professor Roger Hosking
From Cold Regions to Modern Railtracks Dr Nicholas Cavenagh
YouTube presentation Professor T.G. Forbes
Predicting the Onset of Solar Eruptions Associate Professor Graeme Hocking
Coating deformations in the jet stripping process
Andy Drizen
Finding Uniformly Distributed Steiner Triple Systems
Dr Nicholas Cavenagh
Cryptography, latin squares and cutting up triangles
Professor Stan Owocki
What Physics Sets the Upper Mass (Eddington) Limit of Stars? Professor Jongchul Chae
Unsolved Problems in Solar Prominences
Dr Timothy Stokes
Programs as Algebras Associate Professor Kevin Broughan
Three topics in number theory from 2008: the factorial function, flat primes and Lehmer's Euler phi function conjecture Associate Professor Graeme Hocking
A steady flow with unsteady forcing
Jethro van Ekeren
BSc(Hons) Mathematics Student
The Lamb Shift Professor Peter Cameron - FORDER LECTURER 2008
The random graph Professor Peter Cameron - FORDER LECTURER 2008
Sudoku, Mathematics and Statistics
Felicien Bonnefoy
Higher order spectral methods applied to nonlinear ocean waves
Professor Michael Eastwood
Div, grad, curl and all that Professor Igor Shparlinski
Modular Hyperbolas Dr Jochen Garcke
Sparse grids for machine learning Dr Ian Hawthorn
The Banach-Tarski paradox
Vasile Sinescu (PhD student)
Construction of good lattice rules based
on the L∞ weighted star discrepancy
Professor Matt Visser
Analogue spacetimes
Professor Boris Pavlov
Typical problems of analytic perturbation theory on the continuous spectrum Dr Gareth Vaughan
Smoothed particle hydrodynamics for fluids Professor Gary Walsh
Linear recurrence sequences and their connections to cryptography and Diophantine analysis Garry J. Tee
Sir William Rowan Hamilton (1805–1865, Royal Astronomer of Ireland)
Dirk Nuyens
On the construction of rank-1 lattice rules Dr Tim Stokes and Dr Ian Hawthorn
Idempotent semiheaps Professor Martin Bridson (2005 FORDER LECTURER)
The geometry and grammar of 3-manifolds Dr Bart Oldemann (NZIMA Postdoc)
The saddle-node Hopf bifurcation with global reinjection Vasile Sinescu (PhD student)
Construction of rank - 1 lattice rules based on the general weighted star discrepancy Professor R. Bruce Richter (2004 NZMS LECTURER)
A simple proof of Grötzsch's Theorem Dr Mark Harmer
Conformal Mappings of the triangle groups
and a theorem for weighted Laplaceans
(joint work with Gaven Martin and Boris Pavlov) Professor Arieh Iserles
Highly oscillatory quadrature and its applications Dr Shayne Waldron
An introduction to tight frames Associate Professor Chris Bose
Shock waves for the discrete Boltzmann equation Professor Alfred Sneyd and Kirk Spragg (PhD Student)
Liquid-metal oscillations and viscous damping Dr Gabriel Fruit
Propagation of MHD waves in current sheets.
Comparison with CLUSTER data.
Dr Rua Murray
Variational methods for invariant measure approximation: duality and numerical studies Associate Professor Chris Bose
A variational approach to the approximation of invariant measures Professor Ernie Kalnins
Separation of variables for spaces of constant curvature Dr Timothy Stokes
Internalized equality and modal logic Dr Alistair Windsor
Exactly realizable sequences are smoothly realizable
Dr Vadim B. Kuznetsov
Jack polynomials: integral equation, factorization and representation Dr Jiling Cao
Automatic continuity Dr Graham Rickard
Ocean modelling at NIWA Dr Marcel Jackson
The Kuratowski closure-complement problem Kirk Spragg (MATH420Y - BCMS Project Talk )
The shallow water equations: The method of characteristics
and two numerical approximation schemes
Dasha Leonova (MATH421Y - BCMS Project Talk)
Game theory: Repeated games of complete information Iain MacDonald
Edge-waves on beaches of arbitrary profile
Dr A. Ross Barnett
High-precision values of the real Gamma function
Professor Caroline Series (Forder Lecturer 2003)
Why is there hyperbolic geometry in dynamics?
Professor Caroline Series (Forder Lecturer 2003)
Indra’s pearls
Sivajah Somasundaram
Recent results on weak Asplund spaces Dr Ian Hawthorn
The Banach-Tarski paradox (2003) Dr Scott Parkins
Quantum chaos with ultra-cold atoms Dr Mike Meylan
Application of spectral theory to linear water waves
Murray Black
The Applied Mathematics Department at AUT Dr Stephen Joe
Construction of good quasi-Monte Carlo rules for functions in weighted spaces Professor John Brown (Astronomer Royal for Scotland)
Black holes-white rabbits
Dr Anthony Quas
Non-monotonicity in voting systems Professor Rekha Kulkarni
Iterative computation of eigenelements
David Harder
Geodesic geometry of some static axisymmetric vacuum spacetimes Professor Robert Bartnik
General relativity and the concept of mass: An introduction Professor Richard Canfield
Of tilt and twist Dr Michael Bulmer
Equational reasoning as a tool for data analysis Dr Jacob Heekikhuisen
Magnetic reconnection with a generalised Ohm's Law Associate Professor Kevin Broughan
The approximation theorem of Dirichlet
(and Kronecker) and its application
to the Riemann zeta function Dr Warren Moors
Baire category theorem in analysis Dr Rua Murray
Orbit statistics for maps with indifferent fixed points Professor Marston Conder
Hurwitz groups with arbitrary centres Dr Alastair Rucklidge
Quasipatterns in the Faraday wave experiment Dr Ken Louie
Roll me over in the clover-a model for growth of Trifolium repens Dr Carlo Laing
Pattern formation in neural systems Professor Ernie Kalnins
Classical and quantum constants of the motion (explicit techniques) Professor S. Rauch-Wojciechowski
From Jacobi problem of separation of variables to theory of quasi-potential Newton systems Steven Joyce
Symmetry groups of the four-dimensional polytopes Dr Tim Stokes
Traversing the spectrum: from surfaces to semigroups Steven Joyce
Applications of the Baire category theorem to Fourier analysis and the non-differentiability of continuous functions Mirela Domijan
Applications of fixed point theorems to ordinary differential equations Dr Frances Kuo
Constructing good lattice rules with millions of points - an overview of recent developments Gemma Blacklock
Consumer theory Celia Voysey
Viscous damping of periodic water waves Professor James Geelen (NZMS Visiting Lecturer)
An algebraic matching algorithm Professor John Butcher
Numerical methods for ordinary differential equations in the 20th century Professor John Butcher
Some new methods for stiff and non-stiff problems |
Recent Seminars |
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University of Waikato 2004-04-23 G3.33 The Earth magnetosphere is a complex and highly dynamic system. Thanks to the CLUSTER mission launched in 2000, a 3D-picture of this magnetized environment is now available. Particularly, low frequency fluctuations are observed in some key-regions of the magnetosphere known as current sheets (magnetopause, magnetotail...). Such oscillations are also measured in the solar atmosphere where current sheets may form. In order to identify the nature of these perturbations and to explicit their role in the more global dynamics of the system, it is necessary to build a self-consistent model that studies theoretically the response of a current sheet to various excitations.
In this talk, I present an analysis of the propagation of compressive MHD perturbations in the Earth magnetotail (described as being an Harris-type sheet). I solve explicitly the linear response of the plasmasheet to an initial perturbation (initial displacement or external driver) by using the Green formalism. Two kinds of eigenmodes are found: global discrete oscillations of the plasmasheet and continuous localized oscillations that may transfer energy to the plasma through the resonant absorption process.
The theoretical model is then compared to a particular CLUSTER event, when the tetrahedron crossed the plasmasheet. The analysis of the observed fluctuations is carried out with the aim of determining if they are MHD global eigenmodes. If most of the low frequency oscillations do not match the theoretical eigenmodes of the plasmasheet, some higher frequency oscillations linked to a substorm agree remarkably well with the linear response of the sheet to an initial vertical displacement. However, a last perturbation at 0.04Hz is not explained by the MHD model and may represent the first experimental evidence of a tearing mode. |
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