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Highly-oscillatory evolution equations: averaging and numerics

By Mohammed Lemou

Appears in collection : Jean Morlet Chair 2021- Conference: Kinetic Equations: From Modeling Computation to Analysis / Chaire Jean-Morlet 2021 - Conférence : Equations cinétiques : Modélisation, Simulation et Analyse

Usual numerical methods become inefficient when they are applied to highly oscillatory evolution problems (order reduction or complete loss of accuracy). The numerical parameters must indeed be adapted to the high frequencies that come into play to correctly capture the desired information, and this induces a prohibitive computational cost. Furthermore, the numerical resolution of averaged models, even at high orders, is not sufficient to capture low frequencies and transition regimes. We present (very briefly) two strategies allowing to remove this obstacle for a large class of evolution problems : a 2-scale method and a micro/macro method. Two different frameworks will be considered : constant frequency, and variable - possibly vanishing - frequency. The result of these approaches is the construction of numerical schemes whose order of accuracy no longer depends on the frequency of oscillation, one then speaks of uniform accuracy (UA) for these schemes. Finally, a new technique for systematizing these two methods will be presented. Its purpose is to reduce the number of inputs that the user must provide to apply the method in practice. In other words, only the values of the field defining the evolution equation (and not its derivatives) are used.These methods have been successfully applied to solve a number of evolution models: non-linear Schrödinger and Klein-Gordon equations, Vlasov-Poisson kinetic equation with strong magnetic field, quantum transport in graphene.

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Citation data

  • DOI 10.24350/CIRM.V.19735003
  • Cite this video Lemou, Mohammed (22/03/2021). Highly-oscillatory evolution equations: averaging and numerics. CIRM. Audiovisual resource. DOI: 10.24350/CIRM.V.19735003
  • URL https://dx.doi.org/10.24350/CIRM.V.19735003

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Bibliography

  • CHARTIER, Philippe, LEMOU, Mohammed, MÉHATS, Florian, et al. A new class of uniformly accurate numerical schemes for highly oscillatory evolution equations. Foundations of Computational Mathematics, 2020, vol. 20, no 1, p. 1-33. - https://doi.org/10.1007/s10208-019-09413-3
  • CHARTIER, Ph, LEMOU, Mohammed, MÉHATS, Florian, et al. Highly oscillatory problems with time-dependent vanishing frequency. SIAM Journal on Numerical Analysis, 2019, vol. 57, no 2, p. 925-944. - https://doi.org/10.1137/18M1203456
  • CROUSEILLES, Nicolas, JIN, Shi, LEMOU, Mohammed, et al. A micro-macro method for a kinetic graphene model in one space dimension. Multiscale Modeling & Simulation, 2020, vol. 18, no 1, p. 444-474. - https://doi.org/10.1137/18M1173770
  • CHARTIER, Philippe, LEMOU, Mohammed, MÉHATS, Florian, et al. Derivative-free high-order uniformly accurate schemes for highly-oscillatory systems. To appear 2021. - https://hal.inria.fr/hal-03141156

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