Study of electron concentration to help advance plasma treatment technology
A publication by KFU's Problems of Radio Astronomy lab was issued in Plasma Sources Science and Technology.
The authors found a dependence of the electron concentration, electron and gas temperatures in a low-pressure high-frequency inductive discharge on the frequency of the electromagnetic field.
The project is funded by Russian Science Foundation and is titled 'Numerical and experimental study of low-pressure high-frequency plasma for surface modification of functional materials', headed by Associate Professor Aleksandr Shemakhin.
He explains, "High-frequency induction plasma is used in induction motors, it is used to polish lenses, it is used to etch many materials of various nature. As is known, the induction plasma is ignited due to the electromagnetic field formed by the coil. By changing its frequency, it is possible to achieve a significant improvement in the matching of the characteristics of the plasma with the high-frequency generator without increasing the power of the setup. Nevertheless, the frequency dependence of important plasma characteristics, such as the concentration and temperature of electrons, has not yet been determined by physicists in a wide frequency range; most often they have taken 2-3 frequencies used in experiments."
Lab Engineer Timur Terentyev says that the team first researched the dependence of the concentration of electrons on the frequency through numerical modeling, "We assumed that at some frequency there is a peak, the maximum value of the electron concentration. Our assumption was confirmed; this meant that there is a certain frequency of the electromagnetic field, which is better to use for a particular installation. Prior to this, the frequency of the electromagnetic field was chosen based on the allowed set of frequencies. Now the frequency has become a parameter that we can control in order to achieve the best plasma generation performance. This is amazing."
The project participants were able to prove that it is possible to increase the concentration of charged particles, their temperature, and also to obtain the optimal temperature of the carrier gas by adjusting the frequency of the applied high-frequency field. For this, it is not required to make changes to the design of the gas-discharge chamber of a plasma installation. The obtained scientific results will help in the design of new installations for high-frequency plasma processing of materials and will also improve the characteristics of existing ones.
Provided by Kazan Federal University
