Physical understanding of the static magnetic field's synergistic enhancement of cold atmospheric pressure plasma treatment

In the last decades, to improve the CAP treatment efficiency, its biological effects in combination with other physical modalities have widely investigated. However, the physical insight into most of supposed synergistic effects remained elusive. In this regard, the synergetic effect of cold plasma and magnetic field has been used for different applications, especially due to considerable synergistic in biological media reactivity. In the present paper, using a 420 mT N42 magnet, the effect of the perpendicular external static magnetic field (SMF) on the cold atmospheric pressure plasma (CAP) characteristics, such as electron temperature and density, are investigated based on the optical emission spectroscopy, utilizing the Boltzmann plot method, Saha-Boltzmann equation and Specair software simulation. Results showed that the rotational and electronic excitational temperature experienced 100 K and 550 K increases in the presence of SMF, respectively. While the vibrational and translational temperatures remained constant. Moreover, electron temperature estimated as 1.04 eV in the absence of SMF and increased up to 1.24 eV in the presence of SMF. In addition, the Saha-Boltzmann equation illustrated that the electron density increased in presence of the additional SMF. The results of the present study indicated that the magnetic field could be an assistant to the cold plasma effect, beneficial in medical applications due to modifications in plasma temperature and electron density.