Electric discharge during electrosurgery

Abstract

Electric discharge utilized for electrosurgery is studied by means of a recently developed method for the diagnostics of small-size atmospheric plasma objects based on Rayleigh scattering of microwaves on the plasma volume. Evolution of the plasma parameters in the near-electrode sheaths and in the positive column is measured and analyzed. It is found that the electrosurgical system produces a glow discharge of alternating current with strongly contracted positive column with current densities reaching 103 A/cm2. The plasma electron density and electrical conductivities in the channel were found be 1016 cm−3 and (1-2) Ohm−1cm−1, respectively. The discharge interrupts every instance when the discharge-driving AC voltage crosses zero and re-ignites again every next half-wave at the moment when the instant voltage exceeds the breakdown threshold.

Time-resolved measurements of electron density in nanosecond pulsed plasmas using microwave scattering

“…In this paper, a method for direct measurement of electron number density in the plasma column of the NRP discharge in a pin-to-pin electrode configuration by means of Rayleigh microwave scattering (RMS) is presented. This method was recently proposed and successfully applied for measurements in various types of atmospheric pressure microplasmas [28] [29] [30] [31] [32].…”

Effects of cold atmospheric plasma generated in deionized water in cell cancer therapy

“…Plasma density was obtained from plasma conductivity by using the following expression: , where is the frequency of the electron‐neutral collisions, is the plasma density, and is the angular frequency . Plasma conductivity can be expressed as , where , is sqrt(I 2 + Q 2 ) . The volume of the plasma column was determined from the intensified charged‐coupled device (ICCD) images.…”

“…[22] Plasma conductivity can be expressed as U ¼ AσV, where A ¼ 263:8 VΩ=cm 2 , U is sqrt(I 2 + Q 2 ). [23] The volume of the plasma column was determined from the intensified charged-coupled device (ICCD) images. The radius (R) of the streamer column was determined from the size of the central highly luminous filament.…”

Thomson microwave scattering for electron number density diagnostics of miniature plasmas at low pressure

“…The microwave scattering technique was recently proposed for temporal measurement of electron number and electron number density. The technique is used to conduct non-intrusive direct measurements and has been implemented in a number of relative measurements of atmospheric-pressure micro-plasma samples, including atmospheric pressure plasma jet, nanosecond repetitive-pulsed discharges, micro-discharges used for electrosurgery, and laserinduced plasmas [6] [12] [13] [14] . However, microwave scattering has yet to be applied to miniature discharges at low gas pressure.…”