Investigation of optical spectroscopy for the different phases of helium .

The micro-plasma created by corona discharge was established around the point electrode in gas and supercritical helium. The visible light from the microplasma was investigated by optical emission spectroscopy as a function of temperature and pressure. The impurity in the helium gas can be considered the addition to allow acquiring the optical emission spectra from not only the helium but also nitrogen and hydrogen. Profiles of the high resolution emission spectra for several species such as H, N$_{\mathrm{2}}$, N$^{\mathrm{+}}_{\mathrm{2}}$, He$_{\mathrm{2}}$ and He were presented and compared.