Selective Energy Input into Vibrational Energy of Nitrogen Molecule in Non-Self-Sustaining DC Discharge Plasma Source

A Non-Self-Sustaining DC (NSS DC) discharge plasma source aiming for efficient nitrogen vibrational excitation by apparent reduced electric field (E/N) control has been developed. This plasma source utilizes a nanosecond pulse plasma generator and a DC power supply. The superimposed DC voltage controls the apparent E/N suitable for efficient nitrogen vibrational excitation. The ro-vibrational Raman spectrum of the ground state nitrogen molecule is experimentally measured to estimate the vibrational distribution function and the rotational temperature. The vibrational excitation is enhanced with the increase of the apparent E/N, and vibrational level more than v=8 is experimentally observed in the discharge volume. A vibrational relaxation model has been constructed to investigate the relation between vibrational distribution and the energy input with superimposed DC voltage. The model includes vibrational-to-vibrational energy transfer and vibrational-to-translational energy transfer of the nitrogen molecule. The model highlights the importance of energy input with E/N control to efficiently increase the density of vibrationally excited nitrogen molecules. Further details will be discussed at the meeting.