Electrical and spectroscopic characterization of a surgical argon plasma discharge

Abstract

For electrosurgical procedures, the argon plasma coagulation (APC) discharge is a well-established atmospheric-pressure plasma tool for thermal haemostasis and devitalization of biological tissue. To characterize this plasma source, voltage–current measurements, microphotography, optical emission spectroscopy and numerical simulation are applied. Two discharge modes are established during the operation of the APC plasma source. A short transient spark discharge is ignited within the positive half period of the applied high voltage after a streamer channel connects the APC probe and the counter-electrode. During the second phase, which continues under negative high voltage, a glow discharge is stabilized in the plasma channel.

Electron density measurement in atmospheric pressure plasma jets: Stark broadening of hydrogenated and non-hydrogenated lines

“…A similar approach to estimate the current density was used in [22] where a 30 W, 350 kHz discharge, formed of 245 ± 21 μm filaments, was found to have an electron density inside of the channels of approximately 9.9 × 10 15 cm −3 . Using the current density method to establish the electron density is clearly indicative and has numerous pitfalls.…”

Electron density measurements of atmospheric-pressure non-thermal N2 plasma jet by Stark broadening and irradiance intensity methods

“…The density of N þ 2 ðX 2 R þ g Þ is assumed to be approximately equal to the electron density. Functions (16) and (17) can be transformed to (20) and (21) …”

“…Based on the irradiance intensity calibration, the absolute intensity of N 2 (C-B,0-0) at 337.1 nm and N þ 2 (B-X,0-0) at 391.4 nm are used. 21 Compared to the Stark broadening spectroscopic technique, the second method depends on the absolute emission intensity in lieu of the broadening mechanism and can calculate n e lower than 10 14 /cm 3 . 22,23 In addition, nitrogen exists in air and the emission spectra can be acquired easily from the discharge.…”

The Quantum of Action and Finiteness of Radiative Corrections: Deconfining SU(2) Yang-Mills Thermodynamics

“…First, there are small holonomy changes, induced through momentum transfers by plane-wave fluctuations that are largely off their free mass shell 3 , which generate negative ground-state pressure by virtue of a pure-gauge configuration of the effective gauge field [14,16,17]. Second, as we shall make explicit in this paper, just-not-resolved calorons/anticalorons are responsible for pointlike vertices, associated with their dissociation into screened but unresolved monopole-antimonopole pairs on one hand [18] and a rapidly converging loop expansion in the effective theory [19,20,21,22]. We will make clear that this loop expansion, which can naively be organized into an expansion in powers of ≡ h 2π , turns out to be a more subtle expansion.…”

“…Calculating loops in effective variables yields a quantitative description of collective effects as induced by fundamental field configurations [18,23,24,25]. Moreover, since the fields of the effective theory and their interactions do only depend on the contributions of large calorons/anticalorons we would conclude that, on a fundamental level, the mediation of interactions between unresolved off-shell plane-wave fluctuations by calorons/anticalorons (vertices) dies off rapidly with decreasing ρ.…”