@article{oai:nagoya.repo.nii.ac.jp:00007336,
 author = {森, 英男 and MORI, Hideo and 新美, 智秀 and NIIMI, Tomohide and 秋山, 勇雄 and AKIYAMA, Isao and 都築, 巧 and TSUZUKI, Takumi},
 issue = {702},
 journal = {日本機械学會論文集 B編},
 month = {Feb},
 note = {In the present study, we measure the rotational population in supersonic nitrogen free jets using a REMPI (resonantly enhanced multi-photon ionization) method, which is not influenced by secondary electrons, unlike an electron beam method. Nitrogen ions are detected as a REMPI signal and its spectra depending on the wavelength of an irradiated laser beam are analyzed to measure rotational temperature through the Boltzmann plot. Nitrogen gas expands into a vacuum chamber from a sonic nozzle with a D=0.50 mm diameter, setting PoD (Po:source pressure), depending inversely on the nozzle Knudsen number, at 15 Torr・mm or lower. For PoD=15 Torr・mm, the rotational temperature distribution along the centerline of the jet, measured by Boltzmann plot, coincides with Marrone's data measured by electron beam fluorescence, and the rotational relaxation rate Z_R calculated by the relaxation equation results is 1.3. However, the non-Boltzmann rotational distribution appears evidently in the supersonic free molecular nitrogen flows for PoD≤15 Torr・mm and as a decrease in the PoD, the deviation from the Boltzmann distribution and the partial freezing of the population arise more upstream.},
 pages = {436--441},
 title = {超音速自由分子流における非ボルツマン回転エネルギー分布の実験的解析},
 volume = {71},
 year = {2005}
}