Studies of pulsed plasma-ion streams during their free propagation and interaction with SIC-targets

Summary form only given. The paper reports on experimental studies of deuteriumplasma streams during their free propagation in a vacuum chamber and their interaction with a silicon-carbide (SiC) target. The plasma streams were generated by the RPI-IBIS coaxial multi-rod accelerator, which (after the pulse injection of pure deuterium) was powered from a 60-μF condenser bank charged initially to 30 kV. In a so-called medium operational mode an average value of the deuteron energy was about 40 keV [1].The reported optical measurements were carried out trough a side-on optical window, using a quartz collimator and a quartz optical-cable, which was coupled with a Mechelle®900 spectrometer. It could be operated in a wavelength range from about 300 nm to 1100 nm, at different exposition times (from 100 ns to 50 ms) with a chosen delay time (ranging from 100 ns to 1 ms). The spectrometer was equipped with a PCO SensiCam camera and software needed for an analysis of recorded optical spectra. Particular attention was paid to detailed spectroscopic measurements of free-propagating plasma streams and plasma produced at the surface of a SiC target, which was placed at a distance of 20 cm from the electrode ends, and irradiated by powerful (1-5 MW/cm2) deuterium-plasma streams. The main aim was to record and identify spectral lines of carbon and silicon ions. On the basis of the spaceand time-resolved spectroscopic measurements of a DE line, it was estimated that the highest deuterium-plasma density was about 1017 cm-3, while the average value was 3 x 1016 cm-3. Surface changes of the irradiated SiC targets were analyzed with a scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDS). It was shown that plasma-ion fluxes of energy density of about 2-7 J/cm2 are sufficient for material studies. The advantages of the RPI-IBIS system are relatively high energies of the emitted deuterons (ranging up to several hundreds keV), and high power loads upon the target in ion micro-beams spots. The presented results are of importance for basic plasma physics and for fusion-oriented material studies.