Non-thermal plasmas generated at atmospheric pressure are of great interest for biomedical applications related to sterilization and microbial decontamination. These plasmas produce reactive species such as O, N2* and OH radical and atomic O, associated with processes of inactivation of microorganisms and removal of organic materials. In this work we study an electrical discharge capable of generating a plasma plume close to ambient temperature. The discharge is produced between two conducting disks separated by an insulating disk, with a 1 mm central hole through which the operating gas flows. Characteristic voltage-current curves were measured using either air or argon and variable insulator thicknesses between 1 and 10 mm. Also, the discharge emission spectrum was measured.

Los plasmas no térmicos generados a presión atmosférica presentan interés en aplicaciones biomédicas vinculadas a la esterilización y descontaminación microbiana. Este tipo de plasmas produce especies activas como O, N2* y radicales OH, asociadas a procesos de inactivación de microorganismos y a la remoción de materiales orgánicos. En este trabajo se estudia una descarga eléctrica tipo plasma jet capaz de generar una pluma de plasma con temperaturas próximas a la temperatura ambiente. La descarga se produce entre dos discos conductores separados por un disco aislante, con un orificio central de 1 mm a través del cual fluye el gas de operación. Se realizaron mediciones de las curvas características de tensión-corriente empleando aire y argón y variando el espesor del aislante entre 1 y 10 mm. Además, se midió el espectro de emisión de la descarga.

Spectral emission lines from a low pressure d-c arc discharge with a Ti cathode were studied in various ambient gases; N2, O2, and Ar. Light from the plasma was detected by an optical spectrometer multichannel analyzer (OSMA). The spectral intensities of Ti, Ti+, Ar and N2 were measured as a function of the gas pressure in the range 5 × 10-3 - 0.5 mbar. The measurements were performed in the inter-electrode region at different distances from the cathode. For N2 and O2 as the filling gases, the intensities of Ti and Ti+ increase with the gas pressure up to pressure values of the order of 0:2¡0:4 mbar, while they decrease for higher pressure values. With Ar gas, a different behavior of the Ti+ intensity was found; it presents an increasing general trend. The behavior of the lines was qualitatively analyzed in terms of the most relevant atomic processes that take place in the metallic plasma - gas structure (charge-exchange, electron impact excitation and ionization, etc.). It is found that the behavior of the observed spectral lines can be satisfactorily explained in terms of the relevance of these processes as functions of the neutral gas density and electron temperature.

An experimental study of the metallic ion flux in a pulsed copper vacuum arc with an annular anode and operated with an axial magnetic field is presented. It is employed an insulating drift duct surrounded by an external coil which generates an axial magnetic field. Operating the arc under vacuum condition, measurements of the ion flux and the plasma potential at different axial positions along the duct and different magnetic field values are presented. The arc voltage and the total discharge current as functions of the magnetic field intensity are also reported. We find that the decay of the ion flux through the duct walls is not exponential. A simplified model for the ion emission is used in order to obtain an interpretation of the measured ion current for different axial positions and magnetic field strength, and a good agreement with the experimental points is found.