Satyananda Kar, PhD

Atmospheric Pressure Plasma Jet 

   A plasma jet is a device that can produce non-thermal plasma in an open environment and takes the advantage of ambient air while producing different Reactive Oxygen and Nitrogen Species (RONS). These reactive species can be used in a vast variety of industrial (Silicon industry, agriculture, food processing, air and water purification, etc.) and medical (Sterilization, blood coagulation, wound healing and cancer therapy) applications. Biomedical treatments through this plasma jet open a new field of science called plasma medicine, where the research bodies are trying to understand the mechanism of interaction between reactive species and living cells.

   In our Plasma Application Laboratory, an atmospheric pressure RF plasma jet has been designed and developed using different feed gases. RF power is used to excite the plasma as it is the effective mechanism in terms of power coupling (relatively low breakdown voltage and high electron density) and generates a high concentration of reactive species. A study of the electrical, optical and transport characteristics of this plasma is underway by using different diagnostics e.g. voltage and current probes, optical emission spectroscopy, high-speed camera etc. The device is capable of producing a variety of RONS (e.g. NO, NO2, ONOO-, O3, OH, H2O2), UV-photons, ionic species, etc. at low gas temperature and the selection of the species can be controlled by optimizing the input parameters (i.e. applied power, feed gas and electrode geometry).

• Presently we are focusing on understanding the basic physics, viz., to characterize these small volume plasmas, helical structures formation in the argon plasma jet, helium plasma characteristics for different RF pulse-modulated frequencies.

• Based on such insights about the possibilities of control and selectivity of reactive species, this can be fine-tuned to meet the criteria required for different commercial applications.

   

   Considering the vast applications of cold plasma in the field of medical and industries, a low cost, compact AC cold atmospheric pressure plasma jet is also developed. A high voltage sinusoidal signal is used to produce cold atmospheric pressure plasma of around 4 cm plume length. Basic characterization of the plasma parameters is carried out and also ensured that the plasma plume is around at room temperature (< 40 degrees C) as necessary for medical applications.

• Presently, the works are carried out on the efficacy of this cold plasma jet for its anti-microbial effect against drug-resistant bacteria and fungal pathogens.

• The experiments are also extended to dilute raw wastewater, showing the 99.9 % efficiency in the inactivation of stochastic microbes and around 65% conversion of the complex compounds into general minerals. The complete de-colourization of dyes (Rhodamine B, and Methylene blue) using Argon plasma, shows the capability of the developed plasma source for textile and wastewater treatment applications.

• This kind of plasma source can be used for changing the hydrophilicity or hydrophobicity nature of bio-materials.