A5041484940- Geophysical and Geoelectrical Methods
- Geophysical Methods and Applications
- Electromagnetic Simulation and Numerical Methods
- Ionosphere and magnetosphere dynamics
- Seismic Imaging and Inversion Techniques
- Geomagnetism and Paleomagnetism Studies
- Solar and Space Plasma Dynamics
- Advanced Numerical Methods in Computational Mathematics
- Seismic Waves and Analysis
- Electromagnetic Scattering and Analysis
- Earthquake Detection and Analysis
- Non-Destructive Testing Techniques
- Numerical methods in engineering
- Geological and Geophysical Studies
- Underwater Acoustics Research
- Magnetic confinement fusion research
- Magnetic Properties and Applications
Central South University
2021-2024
Memorial University of Newfoundland
2022
National Space Science Center
2007
Chinese Academy of Sciences
2007
Abstract Many studies have highlighted the superior performance of iterative solvers employing auxiliary‐space Maxwell solver preconditioner in controlled‐source electromagnetic induction problems featuring isotropic conductivity. The importance considering presence electrical anisotropy data has been well recognized. However, anisotropic conductivity will impose difficulty robustly solving final system linear equations as may significantly increase its condition number and degrade...
The MHD drift ballooning mode (DBM) instability near the inner edge of near‐Earth plasma sheet is studied by using both one‐fluid generalized progressing wave expansion method and two‐fluid approach. It found that in frame reference at rest relative to bulk DBM may become a purely growing two distinct circumstances, which, for convenience, are called DBM1 DBM2, respectively. β threshold identical with derived Ohtani Tamao [1993] Southwood Kivelson [1987], while criterion DBM2 covers Miura et...
SUMMARY To effectively and efficiently interpret or invert controlled-source electromagnetic (CSEM) data which are recorded in areas with the kind of complex geological environments arbitrary topography that typical, 3-D CSEM forward modelling software can quickly solve large-scale problems, provide accurate responses for geo-electrical models be easily incorporated into inversion algorithms required. We have developed a parallel goal-oriented adaptive mesh refinement finite-element approach...
The drift ballooning mode (DBM) instability near the inner edge of plasma sheet (IEPS) is studied further by including a nonstationary earthward flow and shear in analysis. Both equatorial off‐equatorial regions are considered. It found that presence decelerated destabilizes both M − + branches DBM large portion current IEPS substantially increases growth rate instability. premidnight sector causes conventional to weakly subside, while it slightly enhances for Alfvénic mode. combination...
Efficient forward modeling of electromagnetic (EM) fields is the basis interpretation and inversion EM data, which plays an important role in practical geophysical exploration. A novel extrapolation cascadic multigrid (EXCMG) method developed to solve large linear systems encountered modeling. The original curl-curl equation with arbitrary anisotropic conductivity regularized by including gradient a scaled divergence correction term, edge element used discretize equation. We develop approach...
Fifty‐three substorms measured by Double Star/TC‐1 in the near‐Earth magnetotail from July to October, 2004 are studied. The main features of these events are: (a) Magnetic flux pileup characterized continuous enhancement B z is observed, which starts almost simultaneously with aurora breakup within 1–3 minutes, indicating that substorm onset close relation pileup. (b) Sudden plasma sheet expansion sharp increases ion temperature and density seen all events, occurs typically ∼11 minutes...
In this study, we developed a novel three-dimensional (3D) magnetotelluric (MT) forward modeling algorithm based on the finite-element method and hierarchical semi-structured tetrahedron grids, enabling us to handle arbitrary complex models with irregular geometries mountainous topography effectively. Firstly, discretize governing equation of vector scalar potentials by employing edge element nodal basis functions. This choice can reduce condition number linear system enhance convergence...
SUMMARY Geophysicists today face the challenge of quickly and reliably interpreting extensive controlled-source electromagnetic (CSEM) data sets to map subsurface conductivity structures within realistic geological environments. An ideal 3-D CSEM inversion algorithm using tetrahedral grids should be capable distinguishing different resolution requirements between forward modelling grids, have an optimal parallel strategy that fully exploits inherent independence while also possessing...
Abstract This study presents a parallel and accurate adaptive finite element algorithm for 3-D anisotropic direct current (DC) resistivity forward modeling. It enables the simulation of complex environments, including undulating topography, intricate subsurface structures, arbitrary distributions. The improves goal-oriented posterior error estimation strategy by introducing volume factor into dual problem. improvement not only enhances numerical accuracy measurement points located far from...
Abstract Controlled-source electromagnetic (CSEM) surveys are moving increasingly toward realistic and complicated scenarios where the survey region may contain undulated topography, complex geometries, electrical anisotropy media. In this paper, adaptive finite element numerical method is employed to discrete total electric field equation, which can provide precise (EM) responses even with a coarse initial mesh. The unstructured tetrahedral grid effectively address arbitrary irregular...
ABSTRACT Ground‐penetrating radar (GPR) is commonly used to detect buried and near‐surface geophysical structures. GPR denoising necessary because some level of interference, such as from clutter, random noise and/or the column artefact, are inevitable can cause false geological interpretations. Existing sparse representation methods, including wavelet transformation, curvelet transformation dictionary learning, critical in denoising. However, they perform poorly cases data cannot be...
Abstract The 18-layer residual convolution neural network (ResNet18) were used for 1D audio magnetotelluric(AMT) data inversion. In order to avoid the dependence of traditional iterative algorithm on initial model and calculate sensitivity matrix, we have trained ResNet18 via providing parameters instantaneously. was solve problem deep gradient disappearing. Deep lots sample could improve generalization network. experimental results showed that it obtain reliable inversion synthetic AMT data.
<p>    There is a significant interest in improving the efficiency of 3-D CSEM inversion and obtaining more reliable results. A code using unstructured tetrahedral elements has been developed order to consider topographic effect by directly incorporating it into computational grids. In forward modeling, electric dipole source divided set short dipoles simulate its practical shape, size attitude. We adopt edge-based finite-element method discretize...