Spectral Investigations of Micropinches in the Speed 2 Plasma Focus

Soft X‐radiation mainly emitted by ‘micropinches’ is generated in the driver SPEED 2 by injection of heavy rare gases (e.g. argon) into a discharge of pure deuterium. It has been proved by a fast diagnostic in the VUV range based on a microchannelplate, that the short‐living micropinches with sub‐mm‐size are developing where neckings in the plasma column can lead to local radiative collapses as predicted by the collapse model.Spectra of the whole pinch column in the wavelength range close to the ArXVII ‐resonance line (λ = 0.3948 nm) were used to improve temperature and density determination. The results of computer simulated fits using a Monte‐ Carlo‐method for the photon transport including effects of optical density for evaluation of plasma parameters (electron density 1028 m−3 … 1029 m−3, temperature 1 keV … 1.5 keV) agree well with estimates based on the corresponding model. Spatially resolved spectra reveal that about 90 % of the line radiation stems from micropinches.The energy output in small chan...