Agus L. Soenjaya
agus.soenjaya@asc.tuwien.ac.at
Postdoctoral Researcher
Institute of Analysis and Scientific Computing
TU Wien, Austria
agus.soenjaya@asc.tuwien.ac.at
Postdoctoral Researcher
Institute of Analysis and Scientific Computing
TU Wien, Austria
Hi! I'm Agus, a postdoctoral researcher at the Institute of Analysis and Scientific Computing, TU Wien in NumPDEs group of Prof. Dirk Praetorius. I recently graduated with a PhD in Applied Mathematics from UNSW, supervised by Prof. Thanh Tran (UNSW) and Prof. Ben Goldys (University of Sydney).
My PhD research studies well-posedness and numerical approximations of various deterministic and stochastic PDEs arising in micromagnetics at elevated temperatures. My PhD thesis can be found here.
My research explores how complex physical systems, from the mixtures of fluids to the behaviour of conducting plasmas, evolve over time. These processes are often described by partial differential equations (PDEs). In many cases, they are influenced by random effects, such as thermal fluctuations or microscopic noise. To capture this uncertainty, I work with stochastic PDEs (SPDEs), which combine the laws of physics with randomness. Nonlinearity is an important theme in my work.
My research focuses on developing and analysing stable and structure-preserving finite element methods: computational methods that not only approximate solutions to PDEs or SPDEs accurately but also respect the underlying physical laws, such as conservation of energy or mass. This allows simulations to remain faithful to the true behaviour of the system.
Currently, I am particularly interested in the Landau–Lifshitz–Gilbert and Landau–Lifshitz–Bloch equations (describing magnetisation dynamics), the Cahn–Hilliard-type equations (modelling phase separation in materials and tumour growth), and the magnetohydrodynamics (MHD) equations (governing interaction between plasmas and magnetic fields).
Some recent publications are listed here. A complete list can be found under the 'CV' tab. Click on the link to access the paper.
(with P. Lin and T. Tran) Error analysis of a fully discrete structure-preserving finite element scheme for a diffuse-interface model of tumour growth. IMA J. Numerical Analysis (2026, to appear). arXiv:2509.14486.
Strong convergence of finite element schemes for the stochastic Landau–Lifshitz–Bloch equation. IMA J. Numerical Analysis (2026, to appear). arXiv:2602.18021.
Error analysis of scalar auxiliary variable finite element methods for the Landau–Lifshitz–Bloch equation. Computers and Mathematics with Applications, 217 (2026).
(with B. Goldys and T. Tran) A mixed finite element method for a class of fourth-order stochastic evolution equations with multiplicative noise. ESAIM: Mathematical Modelling and Numerical Analysis, 60, no. 2 (2026)
(with K. Le and T. Tran) The Landau-Lifshitz-Bloch equation in polytopal domains: Unique existence and finite element approximation. IMA J. Numerical Analysis (2026), drag002.
Some recent preprints are listed here. A complete list can be found under the 'CV' tab. Click on the link to access the preprint (or send me an e-mail if no link is available yet!).
A priori error analysis of a mass-lumped midpoint finite element method with a structure-preserving solver for the Landau–Lifshitz–Gilbert equation with Dzyaloshinskii–Moriya interaction. arXiv:2606.16142 (2026).
(with B. Goldys and T. Tran) Error analysis of a divergence-preserving mixed finite element scheme for the incompressible Hall-magnetohydrodynamic equation. arXiv:2605.01764 (2026).
Some work in progress - these will be completed soon!
Thin-film limits of stochastic Landau--Lifshitz equations (2026).
23 July 2026: I'm invited to present at the minisymposium on Numerical analysis of nonlinear PDEs in materials science of CMAM 2026 at TU Wien, Austria. My talk is on Finite element approximations of stochastic micromagnetic models at high temperatures.
22 July 2026: I'm invited to present at the minisymposium on Advances on Structure-Preserving Numerical Methods for Nonlinear PDEs of WCCM ECCOMAS 2026 in Munich, Germany. My talk is on Structure-preserving mixed finite element method for the Hall-MHD equations.
20 May 2026: My PhD degree is officially approved by the faculty! My PhD thesis can be found here. I will begin a postdoctoral research position at the Institute of Analysis and Scientific Computing, TU Wien in July 2026.
6 March 2026: I have finally submitted my PhD thesis for examination!
9 December 2025: I'm presenting at the Computational Mathematics and Stochastic Differential Equations special sessions of the AustMS Meeting 2025 at La Trobe University.