The paper presents a new discharge plasma setup, called plasma gun, allowing the generation of nanosecond duration plasma bullets from a pulsed dielectric barrier discharge reactor. These bullets propagate at very high velocity, up to 5 × 108 cm · s−1, in flexible dielectric capillaries flushed with neon or helium flow rates as low as 100 mL · min−1, over distances of a few tens of centimetres, before inducing plasma plume formation in ambient air. Time resolved nanosecond ICCD imaging show evidence for the channelled structure of the bullets which propagate along the inner surface of the dielectric guide. A few centimetres from the DBD reactor where they are generated, the plasma bullets expand with no connection to the high voltage power source. Non‐thermal air plasma plume production is described by spectroscopic measurements. The plasma gun is likely to be developed for remote high voltage fast commutation or in plasma medicine applications or for the decontamination of small diameter catheters.

This paper describes the development and application of a soft x-ray flash radiography technique. A very compact soft x-ray flash source has been specially designed for these studies. The table-top x-ray source developed in this work emits strong doses, up to one roentgen at the output window, of x-ray photons, with most of them in the characteristic lines of the anode material (photon energy in the energy range 5-10 keV), in pulse of 20 ns FWHM with an x-ray emission zone smaller than . All these characteristics make this source attractive for the x-ray radiography of high-speed phenomena, down to ten nanoseconds duration and/or for the media presenting weak absorption for the harder x-ray photons emitted by more conventional flash x-ray systems. Argon streams in ambient air were chosen as a typical case to enlighten the potentialities of this method. Single-shot radiographs of such an argon jet through rectangular nozzles were obtained. No attempt of quantitative measurement of local density in the argon stream has yet been performed, only the qualitative structure of the jet has been investigated. Nevertheless, these preliminary results enable us to state that the diagnostics of gaseous or plasma media, even at rather low pressures, can proceed using soft x-ray flash radiography.