Calculation of electron density and temperature of plasmas by using new Stark broadening formula of helium lines

In this work, three helium lines are considered to find the density and the temperature of the electrons (N-e and T-e) in a plasma jet. We have, at first, developed a new formula for Stark broadening through an exact contribution of the weak collisions of the free electrons with helium atoms (H-e). So, the sum of the weak and strong collision contributions to the spectral broadening is obtained as a function of the electron density N-e and the electron temperature T-e: it is called the Stark broadening by the electron collisions with H-e atoms. By calculating resonance, Doppler, and van der Waals broadenings, measuring instrumental broadening, and using our experimental profiles, we have inferred the value of the full Stark broadening (by ion and electron collisions) for three helium lines (501 nm, 667 nm, and 728nm). By using a relation between the full Stark broadening and electron collision broadening for each line, we have established a relation between the electron density and the electron temperature of the plasma for each line. The plot of the three corresponding functions N-e(T-e) leads to have a good estimation of the electron density N-e and the electron temperature T-e. The obtained result for N-e and T-e is for a fixed value of the voltage, U, and the frequency, f. Repeated experiments for other values of voltage and frequency give other values of the electron density and the electron temperature. Published under license by AIP Publishing.