大回线源瞬变电磁全域视电阻率定义

Full-domain apparent resistivity definition for large-loop TEM

为了进一步满足精细探测的需要,给出了一种大回线源瞬变电磁全域视电阻率数值计算方法,利用该方法可以快速求取大回线源非中心点处多分量的全域视电阻率.利用贝塞尔函数展开法计算大回线源非中心点垂直分量与水平分量的电磁响应,通过分析非中心点处的多分量电磁响应特征,得到基于磁感应强度的大回线源全域(时间上不分早晚,距离上不分远近)视电阻率计算方法.与现有全区视电阻率方法不同在于:对非中心点处多分量视电阻率进行定义,利用磁感应强度定义不存在假极值现象,无需迭代,计算速度快,精度高.

An efficient numerical calculation method for fulldomain apparent resistivity of non-center large-loop TEM has been developed in this paper to meet the demand of finedetection.Bessel function expansion method was used to calculate the vertical and the horizontal component of the noncenter electromagnetic response.A new full-domain（full-time,full-zone）apparent resistivity of large-loop TEM is proposed according to the characteristic of the non-center point electromagnetic response.Compared with the existing full time domain apparent resistivity computation method,this new method defines the non-center multi-component apparent resistivity with no undershoot/overshoot effect.Moreover,this method has higher precision and quicker computing speed since it does not need any iterative computation.