Diagnostics of non-equilibrium atmosperic plasma jets for cancer therapy

Abstract

Summary form only given. Plasma medicine is a relatively new field that outgrew from research in application of low-temperature (or cold) non-equilibrium atmospheric plasmas in bioengineering. One of the most promising applications of cold atmospheric plasma (CAP) is the cancer therapy. Convincing evidence of CAP selectivity towards the cancel cells has been accumulated. This presentation will review recent research efforts in developing various diagnostics of non-equilibrium atmospheric plasma jets. In particular, we will focus on kHz frequency range discharges. Variety of experimental diagnostic approaches was developed including Rayleigh microwave scattering, Thomson laser scattering, electrostatic streamer scatterers, optical emission spectroscopy, and fast imaging. We will address phenomena related to atmospheric nonequilibrium jets including ionization mechanism, process of ionization front propagation, electrical coupling of the ionization front with the discharge electrodes, distributions of excited and ionized species etc. In general, it was found that there is good electric conductivity of the streamer channel and electrodes potential is transferred to the streamer tip without significant potential. Air content in the helium flow governs streamer propagation along the straight path, its cross-sectional structure, and maximal streamer length. Excitation of the streamer with low frequency high voltage is associated with the streamer initiation at the moment when minimal breakdown conditions are reached.