U-Shaped Ultrahigh Frequency Atmospheric Pressure Plasma Jet With Magnetic Loop Antenna

An atmospheric pressure argon plasma was generated using a magnetic loop antenna with a pulse modulated ultrahigh frequency signal of 850 MHz. Finite-element simulations were performed to study the patterns of gas flow and electromagnetic waves. Fast photography of the plasma jet was used to study temporal behavior of the plasma jet. Emission and mass spectrometry were used to identify active species in the plasma jet. The detected dominant species included excited argon atoms and singly charged ions of argon, nitrogen, oxygen, nitrogen oxide, and water. To study the effect of the plasma jet on biological samples, a thin onion epidermal membrane was treated with the plasma jet. The hydrophobic layer displayed hydrophilic characteristics after treatment for 1 min.