Fig. 1 (IMAGE) Osaka University Caption Equations used in the paper: As delay time needs to be taken into account to consider external radiation, U and A are affected by the charge density q and current density j, which have some delay times that depend on space. Thus, to precisely consider the delay, it is necessary to perform a complex spatial integration calculation with a time shift. Credit Osaka University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.