Multiply charged ions from iodine laser-produced plasma of medium- and high-Z targets

Maximum charge states of ions registered in the far expansion zone from laser-produced plasma of Al, Co, Ni, Cu, Ta, W, Pt, Au, Pb, and Bi are presented. The Thomson parabola spectrometer was used to display a general view of the ion species of an expanding plasma while detailed ion charge-energy spectra were determined by the cylindrical electrostatic ion energy analyzer. The current densities of highly charged ion groups above 20 mA/cm2 were measured by use of an ion collector at a distance of 1 m from the target. The photodissociation iodine laser system PERUN (λ = 1.315 μm, power density up to 1015 W cm−2) was employed as a drive

Ion production by lasers using high-power densities in a near infrared region

Results are presented of experiments on ion production from Ta targets using a short pulse (350-600 ps in focus) illumination with focal power densities exceeding 1014 Wcm-2 at the wavelength of an iodine photodissociation laser (1.315 μm) and its harmonics. Strong evidence of the existence of tantalum ions with the charge state +45 near the target surface was obtained by X-ray spectroscopy methods. The particle diagnostics point to the existence of frozen high charge states (4 MeV) for the highest observed charge states. A tentative theoretical explanation of the observed anomalous charge state freezing phenomenon in the expanding plasma produced by a subnanosecond laser pulse is give

Trachelomonas species as the main component of the euglenophyte community in the Siemianówka Reservoir (Narew River, Poland)

As euglenophytes were found to be especially abundant in the Siemianówka Reservoir, Poland, in July 1994, a detailed floristic survey was made. Among the 40 euglenophyta taxa, Trachelomonas was most frequent, with 29 species. The other taxa were Phacus (5), Euglena (5), Lepocinclis (4) and Monomorphina (1). Nine taxa were first recorded for Poland: Trachelomonas curta var. minima, T. intermedia var. papillata, T. neotropica, T. globularis fo. punctata, T. oblonga var. australica, T. planctonica fo. longicollis, fo. ornata, and var. flexicollis, T. silvatica. Details of ultrastructure are illustrated for 29 taxa. T. volvocina var. coranata and var. papilato-punctata are documented with SEM for the first time

Laser beam propagation in the aerodynamic wake of selected objects

W pracy przedstawiono wyniki badań propagacji wiązki światła lasera w śladzie aerodynamicznym wybranych obiektów. Zaobserwowano zależność między parametrami wiązki światła a kształtem modelowych obiektów. Do analizy wybrano rozkład amplitud natężenia światła, który przybliżono rozkładem gaussowskim. Parametry tego rozkładu mogą być przydatne do oszacowania wybranych parametrów śladu aerodynamicznego.The work presents some experimental examinations of the laser beam propagation in the aerodynamic wake of selected objects (obstacles). Large differences between laser light intensity for used objects were observed. Gaussian distribution (median, variance) for the light intensity was analyzed. In our opinion these parameters are useful for estimation of the aerodynamic wakes

Microorganisms in selected sulphuric springs of the Polish Carpathians

Microorganisms colonising sulphurous waters were found at the bottoms of the spring niches and along spring outflows. Five springs from the Carpathians and two from the Carpathian Foredeep were selected for investigations. Sulphurous flora is represented mainly by sulphuric bacteria. They occur as individual threads, spider-webs, festoons, encrustations and covers. Their colours may be white, creamy, violet, pink and purple. Altogether 31 microorganism taxa: bacteria (16), cyanoprokaryota (3) and algae (12) were identified and illustrated. The bacterial occurrences have been correlated with physico-chemical state of the waters

Studies of plasma and craters produced by the interaction of high-energy sub-nanosecond laser with silver target

The results of measurements of microablation from a silver target irradiated by the high-power PALS laser system in Prague are presented. In this experiment the laser beam of energy of about 110 J in a 400 ps pulse was focused perpendicularly to the massive silver target. The target surface position was changed with respect to the focal spot of the laser beam in the range from -2.5 to 2.5 mm. A set of four ion collectors was used for plasma ion emission measurements. The effect of the laser pulse interaction with the target, i.e. craters and damages formed in the vicinity of the craters, were investigated with the use of scanning electron microscopy (SEM) and optical microscopy methods. The characteristics of the crater were compared with the essential parameters of ion streams emitted from the plasma produced in the same laser shot