| Summary: | Atmospheric pressure plasma, APP, jets, are now attracting great interest because of their potential uses in many applications; for example surface modification and plasma medicine. These applications require an insight into their plasma chemistry, which is strongly influenced by the electron energy distribution function. In this work the dynamic behaviour of a 20 kHz-driven APP jet operating with helium as the main gas and oxygen as an additive is investigated. The jet has a commonly used configuration, a cylindrical quartz tube with two electrodes used to form a dielectric barrier discharge. This atmospheric pressure plasma jet was used to generate non thermal plasma bullets away from the production region. The characteristics of the plasma plume and streamer were diagnosed using, current-voltage measurements, ICCD imaging, and optical emission spectroscopy. Here, the use of Thomson scattering to measure the electron properties in the plasma plume created by 20 kHz was reported. The investigation reveals a "ring-like" radial distribution of both the electron density and temperature. A 532nm Nd:YAG laser beam was focused into the plasma plume. The temporally and spatially resolved spectra of light at 900 to the laser direction were detected. The spectra contain light from Thomson Scattering from electrons, along with Rayleigh and Raman scattering from atoms and molecules. The use of a atmospheric pressure helium non-thermal plasma jet to assist a SCR deNOx reaction over a silver-based catalyst at low temperature using simulated diesel fuels was explored. A coupled IR-plasma reactor was developed allowing direct interaction of the plasma with the catalyst bed whilst accommodating a FTIR spectrometer and NOx analyzer. Two KHz, quartz tube jet designs were developed to operate at low gas flows, one with a circular copper electrode but with a grounded electrode in the reaction area, and the other with a central powered electrode with the vessel as a ground. The catalyst was prepared by the impregnation of ?-AI203 with a silver nitrate solution. NOx and hydrocarbon conversions were studied with toluene and octane on an Ag-catalyst at two different temperatures.
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