Simultaneous estimation of plasma parameters from spectroscopic data of neutral helium using least square fitting of CR-model

In the present work an effort has been made toestimate the plasma parameters simultaneously like—electrondensity, electron temperature, ground state atom density,ground state ion density and metastable state densityfrom the observed visible spectra of penning plasma discharge(PPD) source using least square fitting. The analysisis performed for the prominently observed neutral heliumlines. The atomic data and analysis structure (ADAS) databaseis used to provide the required collisional-radiative(CR) photon emissivity coefficients (PECs) values under theoptical thin plasma condition in the analysis. With thiscondition the estimated plasma temperature from the PPD isfound rather high. It is seen that the inclusion of opacity inthe observed spectral lines through PECs and addition ofdiffusion of neutrals and metastable state species in the CRmodelcode analysis improves the electron temperatureestimation in the simultaneous measurement.