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Title: Spectral Characteristics of Deuterium-, Helium- and Gas-Mixture-Discharges within PF-1000 Facility

Abstract

The paper reports on spectroscopic studies of high-current plasma discharges performed at different gas fillings within the large PF-1000 facility. To study visible radiation (VR) the use was made of a MECHELLE registered 900-spectrometer equipped with the CCD readout. The observations of a PF pinch column were performed at an angle of about 65 deg. to the z-axis, and the viewing field was at a distance of 40-50 mm from the electrode ends. Optical measurements were carried out at 0.5-{mu}s exposition synchronized with a chosen period of the investigated discharge. Differences in the optical spectra, recorded at various deuterium-helium mixtures, were analyzed. Intensities of HeI lines were computed for an assumed electron temperature and compared with the experiment. Estimated plasma concentration in pure-deuterium discharges amounted to 8x1018 cm-3, while that in pure helium shots was (4-7)x1017 cm-3 only. Estimates of the electron temperature, from the ratio of intensities of the chosen spectral lines and the continuum, gave values ranging from 5 eV to 50 eV. The paper presents also some spectra from 'weak shots', which show distinct impurity lines caused by different reasons.

Authors:
 [1]; ;  [2];  [2];  [3]; ; ;  [4]
  1. Institute of Plasma Physics, NSC KIPT, 61-108 Kharkov (Ukraine)
  2. Andrzej Soltan Institute for Nuclear Studies, 05-400 Otwock-Swierk (Poland)
  3. (Poland)
  4. Institute of Plasma Physics and Laser Microfusion, 00-908 Warsaw (Poland)
Publication Date:
OSTI Identifier:
20797907
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 812; Journal Issue: 1; Conference: PLASMA 2005: International conference on research and applications of plasmas; 3. German-Polish conference on plasma diagnostics for fusion and applications; 5. French-Polish seminar on thermal plasma in space and laboratory, Opole-Turawa (Poland), 6-9 Sep 2005; Other Information: DOI: 10.1063/1.2168832; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CHARGE-COUPLED DEVICES; DEUTERIUM; ELECTRIC CURRENTS; ELECTRODES; ELECTRON TEMPERATURE; EMISSION SPECTRA; EV RANGE; HELIUM; PF-1000 DEVICE; PINCH EFFECT; PLASMA; PLASMA DIAGNOSTICS; PLASMA FOCUS; PLASMA IMPURITIES; SPECTROSCOPY; VISIBLE RADIATION

Citation Formats

Tsarenko, A., Malinowski, K., Skladnik-Sadowska, E., Sadowski, M. J., Institute of Plasma Physics and Laser Microfusion, 00-908 Warsaw, Scholz, M., Paduch, M., and Tomaszewski, K. Spectral Characteristics of Deuterium-, Helium- and Gas-Mixture-Discharges within PF-1000 Facility. United States: N. p., 2006. Web. doi:10.1063/1.2168832.
Tsarenko, A., Malinowski, K., Skladnik-Sadowska, E., Sadowski, M. J., Institute of Plasma Physics and Laser Microfusion, 00-908 Warsaw, Scholz, M., Paduch, M., & Tomaszewski, K. Spectral Characteristics of Deuterium-, Helium- and Gas-Mixture-Discharges within PF-1000 Facility. United States. doi:10.1063/1.2168832.
Tsarenko, A., Malinowski, K., Skladnik-Sadowska, E., Sadowski, M. J., Institute of Plasma Physics and Laser Microfusion, 00-908 Warsaw, Scholz, M., Paduch, M., and Tomaszewski, K. Sun . "Spectral Characteristics of Deuterium-, Helium- and Gas-Mixture-Discharges within PF-1000 Facility". United States. doi:10.1063/1.2168832.
@article{osti_20797907,
title = {Spectral Characteristics of Deuterium-, Helium- and Gas-Mixture-Discharges within PF-1000 Facility},
author = {Tsarenko, A. and Malinowski, K. and Skladnik-Sadowska, E. and Sadowski, M. J. and Institute of Plasma Physics and Laser Microfusion, 00-908 Warsaw and Scholz, M. and Paduch, M. and Tomaszewski, K.},
abstractNote = {The paper reports on spectroscopic studies of high-current plasma discharges performed at different gas fillings within the large PF-1000 facility. To study visible radiation (VR) the use was made of a MECHELLE registered 900-spectrometer equipped with the CCD readout. The observations of a PF pinch column were performed at an angle of about 65 deg. to the z-axis, and the viewing field was at a distance of 40-50 mm from the electrode ends. Optical measurements were carried out at 0.5-{mu}s exposition synchronized with a chosen period of the investigated discharge. Differences in the optical spectra, recorded at various deuterium-helium mixtures, were analyzed. Intensities of HeI lines were computed for an assumed electron temperature and compared with the experiment. Estimated plasma concentration in pure-deuterium discharges amounted to 8x1018 cm-3, while that in pure helium shots was (4-7)x1017 cm-3 only. Estimates of the electron temperature, from the ratio of intensities of the chosen spectral lines and the continuum, gave values ranging from 5 eV to 50 eV. The paper presents also some spectra from 'weak shots', which show distinct impurity lines caused by different reasons.},
doi = {10.1063/1.2168832},
journal = {AIP Conference Proceedings},
number = 1,
volume = 812,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}
  • The paper concerns the monitoring of high-current pulse discharges and the determination of the plasma concentration within the dense magnetized plasma by means of optical spectroscopy methods. In experiments with the large PF-1000 facility operated at IPPLM in Warsaw, Poland, attention was paid to the determination of the operational mode and electron concentration under different experimental conditions. To measure the visible radiation (VR) the use was made of the MECHELLE registered 900-spectrometer equipped with the CCD readout. The VR emission, observed at 65 deg. to the z-axis, originated from a part of the electrode surfaces, the collapsing current-sheath layer andmore » the dense plasma pinch-region (40-50 mm from the electrode ends). Considerable differences were found in the optical spectra recorded for so-called 'good shots' and for cases of some failures. Estimates of the electron concentration, which were performed with different spectroscopic techniques, showed that it ranged from 5.56x1018 cm-3 to 4.8x1019 cm-3, depending on experimental conditions. The correlation of the fusion-neutron yield and the plasma density was proved.« less
  • The paper presents results of recent experimental studies with a MAJA-PF plasma-focus facility, as carried out for two different configurations of the end-plate of the central electrode. The main aim was to investigate an influence of the shape and material of the electrode end-plate on the formation and structure of the plasma column as well as to record and identify spectral lines of tungsten. The first version of the end-plate was made of Cu, while the second one had an insert made of a Cu-W alloy. Optical spectra were recorded by means of a Mechelle 900 spectrometer, operated with somemore » delay in relation to a current peculiarity and with exposition times varied from 200 ns to 10 {mu}s. For shots with the Cu electrode spectral lines of deuterium (working gas) and carbon ions were recorded, but tungsten lines were not identified. It was estimated that the electron concentration changed from (8 divide 10)x10{sup 17} cm{sup -3} to about 2x10{sup 17} cm{sup -3} in 5 {mu}s after the current dip. In experiments with the second electrode version, among numerous spectral lines there were identified distinct WI and WII lines. Estimates of the tungsten ion concentration were impossible because of close positions of other lines. Diagrams of changes in the electron density are of importance for applications of DPM streams.« less
  • The paper reports on spectroscopic studies of the interaction of high-current Plasma-Focus (PF) discharges with a CD2 100-{mu}m-fiber within the PF-1000 facility operated at 600-650 kJ. Visible radiation (VR) spectra were recorded with a MECHELLE registered 900 spectrometer at different instants. The exposition was varied from 100 ns to 200 {mu}s. Hydrogen- or deuterium- and carbon-ion-lines were identified. The electron concentration of the core, as estimated from the Stark broadening of the CII-CIV lines, was above 1019 cm-13. From the intensity ratio of carbon-ion lines (CIII/CII and CIV/CIII) it was estimated that the electron temperature of the core was abovemore » 5 eV. For deuterium shots it was observed that the CD2-fiber induced a decrease in the neutron yield (to about 1010), but the obtained spectroscopic data are of interest for understanding of the physical processes.« less
  • The paper presents results of recent experimental studies within the PF-1000 plasma-focus facility [1], which were performed during the free propagation of pulsed plasma-ion streams inside the vacuum chamber, and during their interaction with different targets. Optical spectra were recorder by means of a Mechelle registered 900 spectrometer operated with some delays in relation to the discharge current peculiarity (dip) and with exposition varied from 100 ns to 100 {mu}s. The recorded spectral lines were used to estimate the density of the free-propagating plasma stream. The electron concentration, as estimated from the Stark broadening of the D{sub {beta}} line recordedmore » at a distance of z = 30 cm from the electrode ends, changed from about 4x10{sup 17} cm{sup -3} to 2x10{sup 16} cm{sup -3} in about 30 {mu}s. Analogous spectroscopic measurements were carried out in experiments performed with targets made of carbon and sintered tungsten, which were placed at a distance of 15 cm from the electrode outlet, where q = 10{sup 10} W/cm{sup 2}, and at a distance of 30 cm, where q = 10{sup 9} W/cm{sup 2}. Particular attention was paid to investigation of a plasma layer formed in the front of the target. In that case the electron density, as estimated on the basis of carbon-and deuterium-ion lines, changed from about 3x10{sup 18} cm{sup -3} to 3x10{sup 16} cm{sup -3} in 30 {mu}s. For the target made of the sintered tungsten, which was placed at a distance of 30 cm, the recorded optical spectr a showed intense D{sub {alpha}} and D{sub {beta}} lines as well as CII-CIV lines, which covered tungsten (WI and WII) lines.« less
  • The energy of neutrons and time of their generation are determined from seven scintillation detectors positioned in the axial direction. At the onset, each neutron pulse has beam-target origin with downstream energies in range of 2.7-3.2 MeV. The final part of neutrons has isotropic energy distribution with energies up to 2.6-2.7 MeV. The evolution of the neutron pulses correlates with the visible frames. The first pulse correlates with the fast downstream zipper-effect of the axis layer of the pinch and with the forming of the radiating ball-shaped structure at the bottom of the dilating plasma sheath. The second neutron pulsemore » correlates with the second pinching and exploding of the plasma of lower density and with the structure of the dense plasma at the bottom of the dilating current sheath, similarly to the first pulse. The possible influence of the zipper-effect on the acceleration of deuterons and on the plasma heating is discussed.« less