Anexperimentalinvestigationofananosecondpulseddielectricbarrierdischargeinatmosphericairispresented.Inthesetupaquartztubewasinsertedbetweentheconeandplaneelectrodesinthedirectionparalleltotheelectricfield.Itwasshownthattheappearanceandpropertyofthedischargeweresensitivetothesizeandthepositionofthequartztube.Whenthetubewasplacedonthegroundedplaneelectrode,thedischargeintensitywasfoundtoimprovegraduallywiththeincreaseinthediameterofthequartztube.Furthermore,withanappropriatedistancebetweenthebottomedgeofthequartztubeandtheplaneelectrode,thedischargetendedtoexhibitbetterperformanceingeneratinghomogeneousdiffusiveplasma.Thepossiblemechanismisdiscussed.
