Soft X-ray spectra in regimes with low plasma density and temperature at the L-2M stellarator

Abstract

Soft X-ray plasma emission spectra were measured at the L-2M stellarator in the OH regime with low plasma density (ne ∽ 1019 m-3) and temperature (∽200–400 eV). It is demonstrated that on the X-ray spectra, there is no dip in the energy range corresponding to several thermal energies of electrons or higher. This means that at the L-2M stellarator, the “X-ray dip” phenomenon is not observed, as it was at the T-11M tokamak. In the axial ECRH regime at the heating power P ECRH = 250 kW, the soft X-ray spectra of plasma emission were also measured. In this case, the X-ray dip phenomenon was not observed too.