##### Department of Mathematics,

University of California San Diego

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### Center for Computational Mathematics Seminar

## Shuang Liu

#### UC San Diego

## A parallel cut-cell algorithm for the free-boundary Grad-Shafranov problem

##### Abstract:

A parallel cut-cell algorithm is described to solve the free boundary problem of the Grad-Shafranov equation. The algorithm reformulates the free-boundary problem in an irregular bounded domain and its important aspects include a searching algorithm for the magnetic axis and separatrix, a surface integral along the irregular boundary to determine the boundary values, an approach to optimize the coil current based on a targeting plasma shape, Picard iterations with Aitken's acceleration for the resulting nonlinear problem and a Cartesian grid embedded boundary method to handle the complex geometry. The algorithm is implemented in parallel using a standard domain-decomposition approach and a good parallel scaling is observed. Numerical results verify the accuracy and efficiency of the free-boundary Grad-Shafranov solver.

### April 27, 2021

### 11:00 AM

### Location: Zoom ID 939 3177 8552

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