Tongue-shaped ultrahigh frequency atmospheric pressure plasma jet

Abstract

Summary form only given. Atmospheric pressure plasma jets are gaining growing interest due to their efficacy in diverse fields such as surface treatment, and biomedical applications. In treatment of vulnerable biological materials including membranes and skin, plasma sources must offer stringent provisions such as no risk of arcing and operation at near room temperature to prevent painful sensation or heating of delicate targets. For example, plasma jets generated using pulsed direct current power supplies are often operated at high voltages, raising concerns about increased risk of electrical shock during operation and treatment. We report on generation of a tongue-shaped non-thermal atmospheric pressure argon plasma jet using a magnetic loop1. The plasma jet was formed at a carrier frequency of 850 MHz for 2.5 to 100 KHz pulse modulation frequencies. The plasma was self-sustaining at power and gas flow rate of-1.5 W and 0.5 Lit/m, respectively. The effects of gap size on the resonance frequency were studied using a network analyzer. Plasma formation altered the radiated signal waveform and power from the magnetic loop. In addition, physical and chemical characteristics of the tongue-shaped plasma jet expanding up to 1 cm in the ambient air were investigated by means of mass spectrometry and optical emission spectroscopy. The effects of modulation frequency and gas flow rate on the dynamic behavior of plasma jet were investigated using fast photography.