8 Matching Results

Search Results

Advanced search parameters have been applied.

Effect of deuteron temperature on iron forbidden line intensities in rf-heated tokamak plasmas

Description: Two line ratios, the forbidden line at 845.5 A (2s/sup 2/2p /sup 2/P/sub 1/2/ - 2s/sup 2/2p /sup 2/P/sub 3/2/) to the allowed line at 135.7 A (2s/sup 2/2p /sup 2/P/sub 1/2/ - 2s2p/sup 2/ /sup 2/D/sub 3/2/) in Fe XXII and the forbidden line at 592.1 A (2s/sup 2/2p/sup 4/ /sup 3/P/sub 2/ - 2s/sup 2/2p/sup 4/ /sup 1/D/sub 2/) to the forbidden line at 1118.2 A (2s/sup 2/2p/sup 4/ /sup 3/P/sub 2/ - 2s/sup 2/2p/sup 4/ /sup 3/P/sub 1/) in Fe XIX, have been measured as the ion temperature-sensitive line ratios during rf heating in the Princeton Large Torus. The results indicate that deuteron collisions in plasmas of high deuteron temperature have a noticeable effect on the intensity of the forbidden lines. Measured relative intensities are compared with values from level population calculations, which include deuteron collisional excitation between the levels of the ground configuration. The agreement between the observed and calculated ratios is within 30%. A method for deuteron (or proton) temperature measurement in tokamak plasmas is discussed. 37 refs.
Date: May 1, 1987
Creator: Sato, K.; Suckewer, S. & Wouters, A.
Partner: UNT Libraries Government Documents Department

High-pressure duo-multichannel soft x-ray spectrometer for tokamak plasma diagnostics

Description: A high-resolution, time-resolving soft X-ray multichannel spectrometer (SOXMOS) that permits the simultaneous measurement of emission in two different spectral ranges has been developed and tested extensively for tokamak plasma diagnostics. The basic instrument is a high-resolution, interferometrically adjusted, extreme grazing incidence Schwob-Fraenkel duochromator. The instrument is equipped with two multichannel detectors that are adjusted interferometrically and scan along the Rowland circle. Each consists of an MgF/sub 2/ coated, funneled microchannel plate, associated with a phosphor screen image intensifier that is coupled to a 1024-element photodiode array by a flexible fibrer optic conduit. The total wavelength coverage of the instrument is 5 to 340/sup 0/ A with a measured resolution (FWHM) of about 0.2 A when equipped with a 600 g/mm grating, and 5 to 85 A with a resolution of about 0.06 A using a 2400 g/mm grating. The simultaneous spectral coverage of each detector varies from 15 A at the short wavelength limit to 70 A at the long wavelength limit with the lower dispersion grating. The minimum read-out time for a full spectral portion is 17 ms, but several individual lines can be measured with 1 ms time resolution by selected pixel readout. Higher time resolution can be achieved by replacing one multichannel detector with a single channel electron multiplier detector. Examples of data from the PLT and TFTR tokamaks are presented to illustrate the instrument's versatility, high spectral resolution, and high signal-to-noise ratio even in the 10 A region. 44 refs., 20 figs.
Date: March 1, 1987
Creator: Schwob, J.L.; Wouters, A.W. & Suckewer, S.
Partner: UNT Libraries Government Documents Department

Emission in the 50-80 A region from highly ionized silver in PLT tokamak plasmas

Description: The spectrum of silver emitted by Princeton Large Torus (PLT) tokamak plasmas has been recorded in the 25 to 150 A region by a multichannel time-resolving grazing-incidence spectrometer. Silver atoms have been introduced in the tokamak plasma using the laser blow-off technique. For the first time, lines emitted within the 3p-3d transitions of Ag XXIX, Ag XXX, and Ag XXXI ions, between 50 and 80 A, have been identified.
Date: September 1, 1985
Creator: Schwob, J.L.; Wouters, A.; Suckewer, S.; Cohen, S.A. & Finkenthal, M.
Partner: UNT Libraries Government Documents Department

Spectra in the 60 )angstrom) to 345 )angstrom) wavelength region of elements injected into the PLT tokamak

Description: High resolution spectra of the elements Fe, Ni, Zn, Ge, Se, and Mo injected into the PLT tokamak were recorded by the 2-meter Schwob-Fraenkel soft X-ray multichannel spectrometer (SOXMOS). Spectra were recorded every 50 ms during the time before and after injection. The spectral lines of the injected element were very strong in the spectrum recorded immedately after injection, and the transition in the injected element were easily distinguished from the transitions in te intrinsic elements (C, O, Ti, Cr, Fe, and Ni). An accurate wavelength scale was established using well-known reference transitions in the intrinsic elements. The spectra recorded just prior to injection were substracted from the spectra recorded after injection, and the resulting spectrum was composed almost entirely of transitions from the injected element. A large number of ..delta..n + 0 transitions between the ground and the first excited configurations in the Li I through K I isoelectronic sequences of the injected elements were identified in the wavelength region 60 )angstrom) to 345 )angstrom). 33 refs., 5 figs., 1 tab.
Date: March 1, 1988
Creator: Wouters, A.; Schwob, J.L.; Suckewer, S.; Seely, J.F.; Feldman, U. & Dave, J.H.
Partner: UNT Libraries Government Documents Department

Soft x-ray amplification in lithium-like Al XI (154 /angstrom/) and Si XII (129 /angstrom/)

Description: Recent experiments on soft x-ray amplification in lithium-like ions in a CO/sub 2/ laser-produced recombining plasma confined in a magnetic field are presented. The maximum gain-length products observed are GL approx. = 3 to 4 for the 154 /angstrom/, 4f-3d transition in Al XI and GL (approxreverse arrowequal/ 1 to 2 for the 129 /angstrom/, 4f-3d transition in Si XII, respectively. A one-dimensional hydrodynamic code with a collisional-radiative atomic model was used to model the plasma and the theoretical predictions of gain agree well with the observations. Descriptions of both hydrodynamic and atomic physics code are given. 36 refs., 10 figs.
Date: March 1, 1988
Creator: Kim, D.; Skinner, C.H.; Wouters, A.; Valeo, E.; Voorhees, D. & Suckewer, S.
Partner: UNT Libraries Government Documents Department

Divergence measurements of soft x-ray laser beam

Description: The divergence of the CVI 182 A lasing line generated in a rapidly recombining, magnetically confined plasma column was measured using soft x-ray spectrometers equipped with multichannel detectors. In addition to measurements of the relative divergence, an absolute divergence of approx.9 mrad at a magnetic field of 20 kG and approx.5 mrad at a magnetic field of 35 or 50 kG was obtained by a direct scan of the 182 A axial radiation. Based on this data a peak 182 A intensity of approx.100 kW is obtained. Calculations of the spatial distribution of gain in the plasma were in very good agreement with the experimental data.
Date: July 1, 1986
Creator: Suckewer, S.; Skinner, C.H.; Kim, D.; Valeo, E.; Voorhees, D. & Wouters, A.
Partner: UNT Libraries Government Documents Department

X-ray transitions in highly charged neonlike ions

Description: Wavelength measurements of n=3 to n=2 transitions in neonlike Xe/sup 44 +/, La/sup 47 +/, Nd/sup 50 +/, and Eu/sup 53 +/ have been made using a high-resolution Bragg-crystal spectrometer on the Princeton Large Torus tokamak. The measurements cover the wavelength regions 2.00 to 3.00 (angstrom) and include the electric dipole, and the electric and magnetic quadrupole transitions. The measured wavelengths are compared to energy levels obtained from a multiconfigurational Dirac-Fock calculation. Systematic differences between the experimental and theoretical values are found, which vary smoothly with atomic number. The magnitude of the differences depends on the particular type of transition and ranges from -2.8 eV to +2.2 eV. Inclusion of electron correlation corrections due to ground state correlations and (super) Coster-Kronig type fluctuations in the theoretical energies is shown to reduce the differences for some but not all types of transitions.
Date: November 1, 1987
Creator: Beiersdorfer, P.; von Gjoeler, S.; Bitter, M.; Hinnov, E.; Bell, R.; Bernabei, S. et al.
Partner: UNT Libraries Government Documents Department

Novel target configurations for selective ionization state studies in molybdenum

Description: Details of experiments aimed at achieving low ionization state selectivity in molybdenum are presented. Targets are excited with a 10 J CO{sub 2} laser and the resultant VUV spectrum (300--700 {Angstrom}) has been studied. Combinations of focal spot size, target depth, and target geometries are compared. Simple attenuation of energy is shown not to vary ionization stage composition significantly. Experiments conducted with grazing incidence targets result only in a hot plasma. Modular targets with cooling cylinders of various radii demonstrated good selectivity of the ionization states, but with low absolute signals. Finally, results from combinations of focal spot adjustment and radiative cooling illustrate increased control over desired plasma temperature and density for spectroscopic studies of molybdenum. 7 refs., 14 figs.
Date: March 1, 1990
Creator: Ilcisin, K.J.; Feldman, U.; Schwob, J.L.; Wouters, A. (Princeton Univ., NJ (USA). Plasma Physics Lab.) & Suckewer, S. (Princeton Univ., NJ (USA). Plasma Physics Lab. Princeton Univ., NJ (USA). Dept. of Mechanical and Aerospace Engineering)
Partner: UNT Libraries Government Documents Department