Abstract: A method of electron density measurement    inside discharge channel of pulsed-plasma thruster (PPT) with higher accuracy was proposed,    based on Stark broadening spectrum analysis. By measuring the line profile and the full-width at half-maximum (FWHM) of C atom spectrum emitted by PPT plasma,the electron density can be calculated. But this requires adequate high electron density. If the electron density is lower than 10¹⁶ cm^-3, the accuracy of diagnosis is dramatically decreased. Therefore, a tiny H tracer based on H atom spectrum of the line profile and the full-width at half-maximum was proposed to measure the electron density. Comparing with the conventional method, it can improve remarkably the accuracy of electron density measurement.

Key words: electron density, Stark broadening, analysis of H atom spectrum, pulsed-plasma thruster, high-precision measurement