Pattern formation with a conservation law

Pattern formation in systems with a conserved quantity is considered by studying the appropriate amplitude equations. The conservation law leads to a large-scale neutral mode that must be included in the asymptotic analysis for pattern formation near onset. Near a stationary bifurcation, the u...

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Main Authors: Matthews, P., Cox, Stephen M.
Format: Article
Published: 2000
Online Access:https://eprints.nottingham.ac.uk/49/
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author Matthews, P.
Cox, Stephen M.
author_facet Matthews, P.
Cox, Stephen M.
author_sort Matthews, P.
building Nottingham Research Data Repository
collection Online Access
description Pattern formation in systems with a conserved quantity is considered by studying the appropriate amplitude equations. The conservation law leads to a large-scale neutral mode that must be included in the asymptotic analysis for pattern formation near onset. Near a stationary bifurcation, the usual Ginzburg--Landau equation for the amplitude of the pattern is then coupled to an equation for the large-scale mode. These amplitude equations show that for certain parameters all roll-type solutions are unstable. This new instability differs from the Eckhaus instability in that it is amplitude-driven and is supercritical. Beyond the stability boundary, there exist stable stationary solutions in the form of strongly modulated patterns. The envelope of these modulations is calculated in terms of Jacobi elliptic functions and, away from the onset of modulation, is closely approximated by a sech profile. Numerical simulations indicate that as the modulation becomes more pronounced, the envelope broadens. A number of applications are considered, including convection with fixed-flux boundaries and convection in a magnetic field, resulting in new instabilities for these systems.
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spelling nottingham-492020-05-04T20:32:59Z https://eprints.nottingham.ac.uk/49/ Pattern formation with a conservation law Matthews, P. Cox, Stephen M. Pattern formation in systems with a conserved quantity is considered by studying the appropriate amplitude equations. The conservation law leads to a large-scale neutral mode that must be included in the asymptotic analysis for pattern formation near onset. Near a stationary bifurcation, the usual Ginzburg--Landau equation for the amplitude of the pattern is then coupled to an equation for the large-scale mode. These amplitude equations show that for certain parameters all roll-type solutions are unstable. This new instability differs from the Eckhaus instability in that it is amplitude-driven and is supercritical. Beyond the stability boundary, there exist stable stationary solutions in the form of strongly modulated patterns. The envelope of these modulations is calculated in terms of Jacobi elliptic functions and, away from the onset of modulation, is closely approximated by a sech profile. Numerical simulations indicate that as the modulation becomes more pronounced, the envelope broadens. A number of applications are considered, including convection with fixed-flux boundaries and convection in a magnetic field, resulting in new instabilities for these systems. 2000 Article PeerReviewed Matthews, P. and Cox, Stephen M. (2000) Pattern formation with a conservation law. Nonlinearity, 13 . pp. 1293-1320.
spellingShingle Matthews, P.
Cox, Stephen M.
Pattern formation with a conservation law
title Pattern formation with a conservation law
title_full Pattern formation with a conservation law
title_fullStr Pattern formation with a conservation law
title_full_unstemmed Pattern formation with a conservation law
title_short Pattern formation with a conservation law
title_sort pattern formation with a conservation law
url https://eprints.nottingham.ac.uk/49/