Rocket-borne instrument for measuring vibrational-rotational temperature and density in the lower thermosphere

Abstract

We applied the electron beam fluorescence (EBF) technique to measure the vibrational temperature, rotational temperature, and number density of atmospheric molecular nitrogen (N2) in the altitude range of 100–150km. The atmospheric N2 is excited and ionized by electron beam of the energy of 1keV and the subsequent fluorescence of the N2+ first negative band is detected by a sensitive spectrometer, which covers the 360–440nm wavelength range. In contrast to previous rocket-borne photometric measurements using the EBF technique, the spectrometric measurement provides the above three parameters simultaneously and more accurately. Preflight laboratory experiments were carried out in order to test the spectral sensitivity over the whole spectral range, to calibrate the number density from the band intensity, and to know the accuracy of the rotational temperature measurement. Finally, we tried to calibrate the vibrational temperature measurement by using heated N2 gas which is ejected from the small nozzle.