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Corona discharges: fundamentals and diagnostics

Corona discharges are discussed in this paper as one example of pulsed atmospheric discharges. Other configurations used are the dielectric barrier and the packed bed reactor. Here only the volume discharge will be discussed and not the surface discharge that also plays a role in these last two cases. The paper is divided in two parts. Fundamental processes that are important in corona discharges are treated in the first section. The characteristic properties of the corona will show up clearly here, its fast development in time and space being a dominating feature. It will also be indicated where knowledge of the processes involved is still marginal or even missing. The second part gives an overview of experimental diagnostics that are in use to obtain data of the propagating discharge. Commonly used methods are treated as well as state-of-the-art developments.