Reduced electric field measurements using optical emission spectroscopy on a pulsed DBD in open air

In recent years, the development of cold atmospheric plasma sources that meet the requirements for use in a variety of medical applications has received much attention. For the present study, a flexible dielectric barrier discharge (DBD) device with a square-mesh structured primary electrode is designed. It is specifically intended to generate uniformly distributed plasma when the secondary electrode (the object to be treated) has an irregular shape. The DBD is operated by pulsed excitation in open air. With characteristic length scales of less than 1 mm and typical time scales of up to several tens of nanoseconds, diagnosing the resulting plasma requires careful analysis. In the right conditions, optical emission spectroscopy (OES) offers a non-invasive method to determine the reduced electric field. Two approaches to calculate the reduced electric field from relative band intensities of the N2 second positive system (SPS) and the N2+ first negative system (FNS) are presented, and their applicability and challenges in a pulsed DBD are discussed