MASS-SPECTROMETRY AND OPTICAL SPECTROSCOPY IN N-2-CO2 AND N-2-CH4 PLASMA JETS

A stationary arcjet at low pressure (0.13 mbar) is used to simulate th e properties of the gas how around a vehicle during entry into the atm osphere of Titan and Mars, For simulation of the Titan atmosphere, a g as mixture of 99% N-2 and 1% CH4 was used, and for the Martian atmosph ere, a gas mixture of 97% CO2 and 3% N-2 was used, Two different measu rement techniques are applied to characterize the plasma: 1) optical e mission spectroscopy and 2) mass spectrometry, The composition of the different plasmas, the axial and radial particle distributions of ioni zed and neutral components, and the vibrational and rotational tempera tures were obtained, For the determination of the temperatures a numer ical simulation of the molecular band structures of CN was carried out .