LEMP calculation of cloud-to-ground lightning based on multi-resolution time-domain method

In order to improve the calculation efficiency of fields radiated by cloud-to-ground lightning return stroke, a multi-resolution time-domain (MRTD) method is proposed for cloud-to-ground lightning LEMP calculation. In 2-D cylindrical coordinates, scaling function of Daubechies wavelet is chosen for field expansion, and iterative formula of MRTD method is derivated. The PML absorbing boundary conditions is adopted to truncate the computational domain. LEMP of different distance off the lightning channel was calculated. The results obtained with the finite-difference time-domain method (FDTD) are compared with the MRTD method. Numerical simulation results show that the MRTD method and FDTD method are consistent in calculating LEMP fields. The MRTD method can significantly save both computational memory and CPU computation time with large gird mesh, as well as good numerical dispersion property.