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Optimizing shapes and topology of physical devices is crucial for both scientific and technological advancements, given its wide-ranging implications across numerous industries and research areas. Innovations in shape and topology…

Computational Physics · Physics 2023-10-02 Alexander Luce , Rasoul Alaee , Fabian Knorr , Florian Marquardt

A range of optimization cases of two-dimensional Stefan problems, solved using a tracking-type cost-functional, is presented. A level set method is used to capture the interface between the liquid and solid phases and an immersed boundary…

Mathematical Physics · Physics 2023-01-25 Tomas Fullana , Vincent Le Chenadec , Taraneh Sayadi

Adjoint methods can speed up stellarator optimisation by providing gradient information more efficiently compared to finite-difference evaluations. Adjoint methods are herein applied to vacuum magnetic fields, with objective functions…

Plasma Physics · Physics 2022-02-16 Richard Nies , Elizabeth J. Paul , Stuart R. Hudson , Amitava Bhattacharjee

The shape gradient quantifies the change in some figure of merit resulting from differential perturbations to a shape. Shape gradients can be applied to gradient-based optimization, sensitivity analysis, and tolerance calculation. An…

Plasma Physics · Physics 2019-04-10 Thomas Antonsen, , Elizabeth J. Paul , Matt Landreman

For a given {\it misfit function}, a specified optimality measure of a model, its gradient describes the manner in which one may alter properties of the system to march towards a stationary point. The adjoint method, arising from…

Solar and Stellar Astrophysics · Physics 2015-05-28 Shravan Hanasoge , Aaron Birch , Laurent Gizon , Jeroen Tromp

Using recently developed adjoint methods for computing the shape derivatives of functions that depend on MHD equilibria (Antonsen et al. 2019; Paul et al. 2020), we present the first example of analytic gradient-based optimization of…

Plasma Physics · Physics 2021-04-21 Elizabeth Paul , Matt Landreman , Thomas Antonsen

In the optimization of turbomachinery components, shape sensitivities for fluid dynamical objective functions have been used for a long time. As peak stress is not a differential func- tional of the shape, such highly efficient procedures…

Numerical Analysis · Mathematics 2018-02-15 Hanno Gottschalk , Mohamed Saadi , Onur Tanil Doganay , Kathrin Klamroth , Sebastian Schmitz

A three-dimensional reduction of the two-particle Bethe-Salpeter equation is proposed. The proposed reduction is in the framework of light-front dynamics. It yields auxiliary quantities for the transition matrix and the bound state. The…

Nuclear Theory · Physics 2009-10-31 J. H. O. Sales , T. Frederico , B. V. Carlson , P. U. Sauer

Direct methods for the simulation of optimal control problems apply a specific discretization to the dynamics of the problem, and the discrete adjoint method is suitable to calculate corresponding conditions to approximate an optimal…

This paper proposes a new equation from continuous adjoint theory to compute the gradient of quantities governed by the Transport Theory of light. Unlike discrete gradients ala autograd, which work at the code level, we first formulate the…

Graphics · Computer Science 2020-06-29 Jos Stam

A finite-element method dependant adjoint-based procedure to determine the temperature field of structures based on measured displacements or strains and a set of standard loads is developed and tested. Given a series of force and…

We present an adjoint-based optimization method to invert for stress and frictional parameters used in earthquake modeling. The forward problem is linear elastodynamics with nonlinear rate-and-state frictional faults. The misfit functional…

Numerical Analysis · Mathematics 2024-09-10 Vidar Stiernström , Martin Almquist , Eric M. Dunham

We review the theory of, and develop algorithms for transforming a finite point set in ${\bf R}^d$ into a set in \emph{radial isotropic position} by a nonsingular linear transformation followed by rescaling each image point to the unit…

Computational Geometry · Computer Science 2020-05-12 Shiri Artstein-Avidan , Haim Kaplan , Micha Sharir

Stellarators are a promising route to steady-state fusion power. However, to achieve the required confinement, the magnetic geometry must be highly optimized. This optimization requires navigating high-dimensional spaces, often…

Plasma Physics · Physics 2019-09-25 Elizabeth Paul , Ian Abel , Matt Landreman , William Dorland

This investigation is motivated by the problem of optimal design of cooling elements in modern battery systems. We consider a simple model of two-dimensional steady-state heat conduction described by elliptic partial differential equations…

Numerical Analysis · Mathematics 2013-07-05 Xiaohui Peng , Katsiaryna Niakhai , Bartosz Protas

The shape gradient is a local sensitivity function that provides the change in a figure of merit associated with a perturbation to the shape of the object. The shape gradient can be used for gradient-based optimization, sensitivity…

Plasma Physics · Physics 2020-01-29 Elizabeth J. Paul , Thomas Antonsen, , Matt Landreman , W. Anthony Cooper

Hybrid computational schemes combining the advantages of a method of moments formulation of a field integral equation and T-matrix method are developed in this paper. The hybrid methods are particularly efficient when describing the…

Computational Physics · Physics 2021-12-03 Vit Losenicky , Lukas Jelinek , Miloslav Capek , Mats Gustafsson

This study demonstrates how the adjoint-based framework traditionally used to compute gradients in PDE optimization problems can be extended to handle general constraints on the state variables. This is accomplished by constructing a…

Optimization and Control · Mathematics 2024-08-13 Pritpal Matharu , Bartosz Protas

Adjoint field methods are both elegant and efficient for calculating sensitivity information required across a wide range of physics-based inverse problems. Here we provide a unified approach to the derivation of such methods for problems…

Geophysics · Physics 2011-09-20 Alireza Aghasi , Eric L. Miller

A high-energy muon collider scenario requires a "final cooling" system that reduces transverse emittance by a factor of ~10 while allowing longitudinal emittance increase. The baseline approach has low-energy transverse cooling within…

Accelerator Physics · Physics 2015-02-11 David Neuffer
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