In physics, “plasma” is a special excited gas, sometimes named “the fourth state of matter”, which is generated by supplying sufficient energy to the gas. Non-thermal atmospheric pressure plasmas, also called low temperature or cold atmospheric plasmas (CAP), are specific types of plasmas which are typically generated by applying electromagnetic fields to a vector gas. In many cases, average electron energy (0.1–10 eV) is significantly higher than the energy of heavy particles. This allows CAP sources to produce a chemically rich environment (O3, 1O2, H2O2, OH, etc.) very close to room temperature; a condition which enables the delivery of reactive species in a non-destructive way to different surfaces, such as organic tissues.
In my research group, we develop numerical models to investigate such types of plasmas. We employ a so-called drift-diffusion-reaction type fluid model to study the properties of plasma such as electric fields, conductivity, density of plasma species, etc. Our research is complemented by experimental studies from other groups of the Alliance.
The movies show the propagation of streamer plasmas in a needle-planar geometry in air at standard temperature and pressure; top: negative polarity, bottom: positive polarity. The streamers initiate from the needle electrode and propagate until they bridge the gap. The color coding indicates the electric field profile of the streamer plasmas.
The main researcher involved in this project is Behnaz Bagheri