Spatial resolution of discharge plasma spectroscopy measurements in gases

Artificially generated plasma is one of the most established diagnostic tools in astrophysics and plasma physics. A critical challenge for such diagnostic techniques is minimizing the intrusiveness of plasma generation processes while enabling multidimensional measurements and enhancing spatial resolution. Atmospheric pressure discharge plasma has emerged as a prominent method of plasma generation, owing to its low equipment requirements and the high number density of active particles within the plasma. Here, we present the high spatio-temporally resolved spectroscopy to investigate the intrusiveness of atmospheric pressure discharge plasma in gases. A femtosecond laser was employed to initiate stable homogeneous discharges under ambient conditions. Through high spatio-temporally resolved spectroscopy, we demonstrate that no material transport occurs within the discharge plasma over experimentally relevant timescales. This finding confirms that discharge plasmas preserve the in situ information of the flow field with negligible perturbation. The spatial resolution of femtosecond laser extended electrode discharge spectroscopy based on discharge plasma is determined by the signal acquisition system. In this study, the resolution was about 50 μm.