Electric field measurement in DC corona discharge in atmospheric pressure air using E-FISHG and laser-triggering methods

Abstract

Electric field measurement using electric-field-induced second-harmonic generation (E-FISHG) draws attention because of its non-invasiveness and is increasingly being applied to various discharge plasmas. However, measurement accuracy of previous studies is unclear since approximations in calibration are inadequate. Therefore, we have developed a measurement and analysis method that does not require approximations and can furthermore obtain the distribution of the electric field. To demonstrate the applicability of the proposed method to discharge plasmas, in this paper, we measure the electric field as a result of the space charge generated by DC corona discharge in atmospheric pressure air and validate the results by comparing them with those obtained using the laser-triggering method. We demonstrate that the electrostatic field and electric field resulting from the space charge can be measured with a difference of about 10% between the results obtained from the laser triggering method and E-FISHG method. The proposed method holds potential for applications in discharge plasmas.