MW-FDTD法を用いた数値地図と傾斜放電路による雷放電電磁界解析

摘要

近年，FDTD (Finite-Difference Time-Domain)法を用いた雷放電電磁界解析が広く行われているが，FDTD法は大規模解析では計算量と使用メモリ増加の問題があり，大規模領域での計算や実際の地形を想定した計算は行われていなかった.そこで我々は，FDTD法の計算量と使用メモリを低減するMoving Window FDTD (MW-FDTD)法の3次元並列計算手法を提案し，地形モデルを用いた大規模雷放電電磁界解析に適用している.しかしながら，波源には単純な線状電流源を用いており，詳細な放電路のモデル化は行っていなかった.そこで本稿では，3次元MW-FDTD法による雷放電電磁界の放電路角度依存性を解析し，放電路の傾きによる観測電磁界への影響を明らかにする.%Analysis of lightning electromagnetic field using the finite-difference time-domain (FDTD) method have been studied in recent year. However, large-scale analysis on real environment have not been considered, because the FDTD method requires huge computational cost on large-scale analysis. We proposed a three-dimensional moving window FDTD (MW-FDTD) with parallel computation and applied this method to large-scale analysis of lightning electromagnetic field with a real terrain model. However, we have used a simple linear current source for lightning channel. In this paper, we have studied about analysis of dependency on channel angle of lightning electromagnetic field using our MW-FDTD with parallel computation with a digital terrain model. We have given an account of effects on electromagnetic field by channel angle.