Experimental study of a multipoint cathode corona in an argon flow
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Experimental Study of a Multipoint Cathode Corona in an Argon Flow B. B. Baldanov Department of Physical Problems, Buryat Science Center, Siberian Branch, Russian Academy of Sciences, UlanUde, Republic of Buryatia, 670047 Russia Received October 21, 2008; in final form, December 10, 2008
Abstract—Results are presented from experimental studies of a multipoint negative corona in an atmo sphericpressure argon flow. It is shown that a decrease in the interpoint distance, gas circulation through the discharge gap, and the adjustment of ballast resistances in the corona supply circuit allow one to stabilize the discharge and enlarge the operating range of discharge currents. PACS numbers: 52.80.Hc DOI: 10.1134/S1063780X09070034
1. INTRODUCTION In recent years, studies of nonequilibrium low temperature atmosphericpressure plasmas and meth ods of generating them have attracted considerable interest. To a large extent, this is related to the pros pects of application of such plasmas in different fields of science and technology, such as cleaning of exhaust gases, generation of ozone, and development of effi cient plasmachemical reactors [1−4]. An efficient means for generating nonequilibrium lowtemperature plasma is the atmosphericpressure glow discharge (APGD) on the basis of a corona dis charge [5, 6]. The main advantages of this discharge, as compared to barrier and corona discharges, are high homogeneity and relatively low cost, as well as the pos sibility of widely varying the dimensions of the dis charge unit. To achieve efficient APGD operation, special measures should be applied to stabilize the negative corona. This allows one to substantially increase the threshold current for spark breakdown in electrically negative [7−10] and positive [11−13] gases. In this case, a new type of discharge—an atmo sphericpressure diffuse glow discharge generating a steadystate homogeneous nonequilibrium plasma in the entire interelectrode gap—appears in the interme diate current range between the corona and spark dis charges [7]. Increased interest in studying the transi tion of a pulseperiodic negative corona into the APGD regime stems from the possibility of using APGDs as a promising new source of nonequilibrium atmosphericpressure plasma [8−10]. An APGD is usually produced with the help of an electrode system with point corona electrodes and a plane anode (see, e.g., [7, 14, 15]). Such systems are more reliable and more vibrostable than extended wirearray systems and allow one to achieve higher
current densities ( J ~ 10 mA/cm2) and higher reduced electric fields (E/N ~ 75–100 Td, where N is the gas density) in the interelectrode gap as compared to those in a conventional point−plane negative corona [7]. The unique APGD properties have stimulated studies aimed at increasing the efficiency of the system (see, e.g., [15−17]). In [15], a multipoint negative corona was investigated in order to find conditions for increasing the current at which spark breakdown of the discharge gap occurs. In
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