可控源时间域电磁响应三维正演数值模拟研究

项目名称： 可控源时间域电磁响应三维正演数值模拟研究

项目编号： No.41504096

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 天文学、地球科学

项目作者： 毛玉蓉

作者单位： 长江大学

项目金额： 23万元

中文摘要： 复杂三维模型的时间域电磁响应正演算法目前还达不到用于处理实际资料的水平。研究时间域电磁响应的快速高效算法，在工作站级平台上实现大数据集、大尺度模型电磁响应的高精度正演模拟，对于电磁勘探方法的理论研究和电磁资料的三维反演具有重要意义。项目组前期用大功率的脉冲电流或阶跃电流作为激励源，采用时域有限差分（FDTD）算法求取了三维地电模型的二次场晚时的稳定响应，在图形处理器（GPU）上提升了计算速度。本课题将进行带地形的三维模型的电磁响应的计算，向空气中延拓网格，进行精细剖分。研究带地形的差分格式，在空间步长、边界条件、初始值上进一步研究以提高算法的自适应性。拟采用信息传递接口（MPI）在高性能计算机实现并行计算，优化FDTD算法在CPU/GPU上进一步提高正演计算速度，达到反演应用实用化的要求。实现大尺度复杂模型的高精度网格剖分和不同激励波形、不同发射天线、不同位置场源组合的激励源的响应计算。

中文关键词： 时域数值算法；瞬变电磁；三维电磁响应；并行计算

英文摘要： So far, the complex 3D model of time domain electromagnetic response forward modeling algorithm is not perfect enough to process the actual data.It is important for the theoretical studies of the electromagnetic prospecting method and 3D inversions of electromagnetic data to realize the high precision forward modeling of large data sets and large scale models with a fast and efficient algorithm in time domain electromagnetic response. The secondary fields of 3D model governed by Maxwell’s equations have been solved by the finite difference time domain （FDTD）algorithm，which is stable late time response of 3D simple model excited by high power pulse current or step current. The calculation speed has been increased by running on the graphic processor（GPU）. Based on it，the electromagnetic response of 3D model with terrain will be calculated. In the air, the Yee’s scheme will be divided the simulation region into rectangular mesh finely. The difference algorithm with terrain、grid size、boundary condition and initial fields will be studied to enhance the adaptability of FDTD algorithm. Message Passing Interface (MPI) running on high performance computer is firstly used to compute in parallel, then optimized FDTD algorithm running on Graphic Processing Unit (GPU) is used to speed up calculations to enhance the computing efficiency of forward modeling and meet practical application requirements of inversion. It is lastly to realize high precision grid subdivision of large scale complex models and electromagnetic response calculation of different forms source, including different motivation waveform, different transmitting antenna and different locations.

英文关键词： Time-domain Numerical Algorithm;TEM;3D Electromagnetic Response;Parallel Computing