Numerical description of discharge characteristics of the plasma needle

Abstract

The plasma needle is a small atmospheric, nonthermal, radio-frequency discharge, generated at the tip of a needle, which can be used for localized disinfection of biological tissues. Although several experiments have characterized various qualities of the plasma needle, discharge characteristics and electrical properties are still not well known. In order to provide initial estimates on electrical properties and quantities such as particle densities, we employed a two-dimensional, time-dependent fluid model to describe the plasma needle. In this model the balance equation is solved in the drift-diffusion approach for various species and the electron energy, as well as Poisson's equation. We found that the plasma production occurs in the sheath region and results in a steady flux of reactive species outwards. Even at small ͑Ͻ0.1% ͒ admixtures of N 2 to the He background, N 2 + is the dominant ion. The electron density is typically 10 11 cm −3 and the dissipated power is in the order of 10 mW. These results are consistent with the experimental data available and can give direction to the practical development of the plasma needle.

Killing of S. mutans Bacteria Using a Plasma Needle at Atmospheric Pressure

“…Studies of this type will be useful, among other thing, for providing benchmark data for modeling. We note that modeling efforts for the plasma needle device have recently begun [30].…”

The dominant role of impurities in the composition of high pressure noble gas plasmas

“…7,8 The chemical reaction set used in the model is composed from publications on discharge modeling found in literature 1,9-11 and consists of 18 chemical reactions which are shown in Table I and an extra electron energy loss term for the production of radiative species. 12 The experimental setup under consideration is very similar to the setup used by Massines et al 13 and Mangolini et al 1 for the sake of comparison with experiment. The configuration consists of two parallel electrodes both covered with alumina dielectrics ͑⑀ r =9͒ of 1 mm thickness.…”

Current status of microplasma research

“…According to their simulation, it is estimated that the plasma density of their source is on the order of 10 11 cm −3 and the major charged species are N 2 + ions produced via the Penning ionization of He * metastable atoms, while the active species interacting with bio materials downstream may be O, O 2 * , O 3 , OH, etc. produced from ambient O 2 and H 2 O [59].…”