Air pollution is one of the top 5 risks causing chronic diseases according to WHO and airborne transmitted pathogens infection is a huge challenge in the current era. Long living pathogens and small size aerosols are not effectively dealt with by the available indoor air purifiers. In this work, a dielectric barrier discharge (DBD) based portable cold-plasma detergent in environment device is reported and its disinfection efficiency has been analyzed in the indoor environment of sizes up to 3 × 2.4 × 2.4 m³. The deactivation efficiency of total microbial counts (TMCs) and total fungal counts (TFCs) is found to be more than 99% in 90 min of continuous operation of the device at the optimized parameters. The complete inactivation of MS2 phage and Escherichia coli bacteria with more than 5 log reduction (99.999%) has also been achieved in 30 min and 90 min of operation of the device in an enclosed environment. The device is able to produce negative ions predominantly dominated by natural plasma detergent along with positive ions in the environment similar to mother nature. The device comprises a coaxial DBD geometry plasma source with a specially designed wire mesh electrode of mild steel with a thickness of 1 mm. The need for feed gas, pellets and/or differential pressure has been eliminated from the DBD discharge source for efficient air purification. The existence of negative ions for more than 25 s on average is the key advantage, which can also deactivate long living pathogens and small size aerosols.

A structurally simple dielectric barrier discharge based mercury-free plasma UV-light source has been developed for efficient water disinfection. The source comprises of a dielectric barrier discharge arrangement between two co-axial quartz tubes with an optimized gas gap. The outer electrode is an aluminium baked foil tape arranged in a helical form with optimized pitch, while the inner electrode is a hollow aluminium metallic rod, hermetically sealed. Strong bands peaking at wavelengths 172 nm and 253 nm, along with a weak band peaking at wavelength 265 nm have been simultaneously observed due to plasma radiation from the admixture of xenon and iodine gases. The developed UV source has been used for bacterial deactivation studies using an experimental setup that is an equivalent of the conventional house-hold water purifier system. Deactivation studies for five types of bacteria, i.e., E. coli, Shigella boydii, Vibrio, Coliforms and Fecal coliform have been demonstrated with 4 log reductions in less than ten seconds.

The experimental study of a tapered, multi-gap, multi-aperture pseudospark-sourced electron gun based X-band plasma assisted slow wave oscillator is presented. The designed electron gun is based on the pseudospark discharge concept and has been used to generate a high current density and high energy electron beam simultaneously. The distribution of apertures has been arranged such that the field penetration potency inside the backspace of the hollow-cathode is different while passing through the tapered gap region. This leads to non-concurrent ignition of the discharge through all the channels which is, in general, quite challenging in the case of multi-aperture plasma cathode electron gun geometries. Multiple and successive hollow cathode phases are reported from this electron gun geometry, which have been confirmed using simulations. This geometry also has led to the achievement of ∼71% fill factor inside the slow wave oscillator for an electron beam of energy of 20 keV and a beam current density in the range of 115–190 A/cm² at a working argon gas pressure of 18 Pa. The oscillator has generated broadband microwave output in the frequency range of 10–11.7 GHz with a peak power of ∼10 kW for ∼50 ns.

In this paper, a high current linear aperture radial multichannel Pseudospark switch (LARM-PSS) is reported which has been analyzed for its high current characteristics. In order to enhance hold-off voltage and support hollow cathode effect for the ignition of the discharge in this configuration, the field penetration analysis through circular and linear apertures of the electrodes has been carried out. The linear apertures in the electrodes increase the current handling capacity than that of circular aperture electrodes without significant compromise of the hold-off capacity. The developed LARM–PSS switch is capable to hold voltage up to 25 kV at gas pressure between 10 and 50 Pa for hydrogen. The switch has been operated using a 800 nF capacitor bank and conducted an effective charge up to 1.5 C with peak switch current ∼20 kA at applied voltage 19 kV.

This paper reports the development of a sealed-off double-gap pseudospark switch and its performance analysis. The modular pseudospark geometry has two gaps that are separated by a cavity drift space region. It utilizes a single ferroelectric trigger unit in a hollow cathode region of the first gap to initiate the discharge for rapid breakdown of both the gaps. The switch has been pinched for deuterium gas and a gas reservoir has been used for maintaining optimum gas pressure in the sealed-off device. The switch design has been analyzed for higher hold-off voltage with high charge transfer capability at higher repetition rates. The developed switch holds a 50 kV voltage in vacuum, and 40 kV during gas discharge at optimum gas pressure with a peak anode current of 8 kA and pulse duration of 1.3 μ s while it is operated with a resistive load of 2.9 Ω. The switch has been tested using a constant current charging power supply for pulse repetition frequency up to 50 Hz at different voltages and peak currents corresponding to 200 nF energy storage capacitors. Its performance has been analyzed in terms of pulse parameters including hold-off voltage, jitter, fall time, rise time, peak current and delay time to qualify the design.