Limitations of the Cooray–Rubinstein Formula: A Time-Domain Analysis Based on the Cagniard–DeHoop Technique

Limitations of the Cooray-Rubinstein formula are studied analytically with the aid of the Cagniard-DeHoop technique. A closed-form approximate expression for the azimuthal magnetic field on the ground is derived and numerically evaluated. The resulting correction term that reveals the limitations of the formula and its outcomes are briefly discussed.