To address the three-dimensional (3D) forward modeling problem of transient electromagnetic fields for grounded-wire source, this paper explores a finite element forward modeling method that employs a frequency-time transformation and background-scattered field separation strategy. It utilizes the vector finite element theory, and the 3D model is discretized using structured hexahedral mesh. Subsequently, the frequency-domain numerical response is computed using the MUMPS solver. Ultimately, the time-domain transient electromagnetic response is derived via cosine transformation. On this basis, the reliability of the forward algorithm is validated using both a one-dimensional layered model and an open three-dimensional model, and its computational accuracy is assessed. Theoretical examples show that the calculation results of the 3D transient electromagnetic forward modeling proposed in this paper are accurate and can meet the calculation requirements of 3D inversion research.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |