TY - JOUR T1 - A Finite Element Method by Patch Reconstruction for the Quad-Curl Problem Using Mixed Formulations AU - Li , Ruo AU - Liu , Qicheng AU - Zhao , Shuhai JO - Advances in Applied Mathematics and Mechanics VL - 2 SP - 517 EP - 537 PY - 2024 DA - 2024/12 SN - 17 DO - http://doi.org/10.4208/aamm.OA-2024-0086 UR - https://global-sci.org/intro/article_detail/aamm/23732.html KW - Quad-Curl problem, mixed formulation, patch reconstruction. AB -
We develop a high order reconstructed discontinuous approximation (RDA) method for solving a mixed formulation of the quad-curl problem in two and three dimensions. This mixed formulation is established by adding an auxiliary variable to control the divergence of the field. The approximation space for the original variable is constructed by patch reconstruction with exactly one degree of freedom per element in each dimension and the auxiliary variable is approximated by the piecewise constant space. We prove the optimal convergence rate under the energy norm and also suboptimal $L^2$ convergence using a duality approach. Numerical results are provided to verify the theoretical analysis.