[15p-B309-1~19] 8.1 Plasma production and diagnostics

[15p-B309-1] [The 44th Paper Award Speech] Optical emission spectroscopy of non-equilibrium atmospheric-pressure plasmas--measurement of electron energy distribution function

Hiroshi Onishi¹, Fuminori Yamazaki¹, Yoshiro Hakozaki¹, Masaki Takemura¹, Atsushi Nezu¹, 〇Hiroshi Akatsuka¹ (1.Tokyo Tech.)

Keywords:atmospheric-pressure non-equilibrium plasma, continuum spectrum, electron energy distribution function

The electron energy distribution function (EEDF) of non-equilibrium atmospheric pressure plasmas can be obtained by OES measurement of the continuous spectrum due to e-a bremsstrahlung. If the obtained spectrum is applied to a theoretical formula, it becomes a Volterra integral equation of the first kind, and EEDF can be solved in principle. However, since the measurable wavelength range is finite, general solvers cannot be used. Therefore, the electron energy probabilistic function EEPF=EEDF/√E was determined so as to minimize the fitness parameter as the objective function. As a result, the EEPF was found to be a two-temperature Maxwellian distribution with a bend near 2.8 eV. The bulk component was about 0.26-0.29 eV, and the tail component was about 2.2-3.0 eV. It was found that this method does not provide information about electrons with lower energies than the photons being measured, while information about higher energies can be obtained with poor accuracy.