1. TIME-RESOLVED OPTICAL SPECTROSCOPY OF HIGH-TEMPERATURE PLASMAS M.J. Sadowski  , K. Malinowski , E. Skladnik-Sadowska , M. Scholtz , A. Tsarenko ¤ and J. Zebrowski   The Andrzej Soltan Institute for Nuclear Studies (IPJ), 05-400 Otwock-Swierk, Poland  Institute of Plasma Physics and Laser Microfusion (IPPLM), 00-908 Warsaw, Poland ¤ Institute of Plasma Physics, NSC KIPT, 61-108 Kharkov, Ukraine SPIE Intern. Congress, Warsaw 2005 1/33

2. Outline of the talk 1. Introduction 2. Measuring equipment for time-resolved spectroscopy 3. Spectroscopic measurements within PF-360 facility 4. Spectroscopic measurements in PF-1000 facility 5. Spectroscopic measurements in RPI-IBIS facility 6. Summary and conclusions SPIE Intern. Congress, Warsaw 2005 2/33

3. The main phases of the PF discharges are well defined and they can easily be identified in any experiment. SPIE Intern. Congress, Warsaw 2005 3/33

4. General view of PF-360 chamber and some diagnostic equipment. SPIE Intern. Congress, Warsaw 2005 4/33

5. Ion pinhole image (left picture), as obtained in a 20-kJ PF device by means of a nuclear track detector covered with 1.5-µm-thick Al-filter which transmitted deuterons of energy > 220 keV, and corresponding ion flux density map (right picture). SPIE Intern. Congress, Warsaw 2005 5/33

6. SSNTDs were placed at different angles to the z-axis, and the recorded ion tracks enabled to determine the angular distribution. 6/33 SPIE Intern. Congress, Warsaw 2005

7. Thomson parabola tracks, which show the mass- and energy- distribution of impurity ions observed in a PF-discharge performed at considerable air remnants and Ar admixture. SPIE Intern. Congress, Warsaw 2005 7/33

8. PF pinch dynamics studies in the PF-360 facility. Two VR pictures (on the left) were taken with 1-ns exposition, 31 ns and 41 ns after the maximum pinch, and the X-ray image (on the right) was recorded at 28 ns. Correlation of intense emitting micro-regions can be observed. 8/33 SPIE Intern. Congress, Warsaw 2005

9. Optical spectra recorded in PF-1000 experiment at a long- and short- exposition, which show large differences in D- and impurity lines. SPIE Intern. Congress, Warsaw 2005 9/33

10. MECHELLE ® 900 optical spectrometer with a CCD camera. SPIE Intern. Congress, Warsaw 2005 Wavelength range: 200 nm – 1100 nm Entrance aperture: 20x150µm Exposition: 100 ns - 50ms Resolution test: 404.7nm,FWHM=0.46nm,  / = 900 1014.0nm,FWHM=0.95nm,  / =1070 10/33

11. SPIE Intern. Congress, Warsaw 2005 Scheme of the PF-360 experiment, which shows diagnostic arrangements for spectroscopic measurements. 11/33

12. SPIE Intern. Congress, Warsaw 2005 General view of the PF-360 experimental chamber and diagnostic equipment used for high-speed photography. 12/33

13. SPIE Intern. Congress, Warsaw 2005 Typical traces from PF-360 experiment: I - discharge current, VR - optical signal from the plasma front, M - marker for the spectrometer synchronization, N – fusion-neutron induced signal. VR I M N  s/div 13/33

14. SPIE Intern. Congress, Warsaw 2005 Optical spectra of PF-360 discharges, as recorded in PF-360 at two positions (z = 2.5 cm and z = 35 cm) with the exposition of 100 µs. 14/33

15. SPIE Intern. Congress, Warsaw 2005 Temporal changes of the VR spectrum recorded with 2-µs expositions. 15/33

16. SPIE Intern. Congress, Warsaw 2005 Temporal changes of the Balmer lines, as recorded in the PF-360 experiment at a distance of z = 35 cm 16/33

17. SPIE Intern. Congress, Warsaw 2005 Temporal changes of the electron concentration and temperature, Temporal changes of the electron concentration and temperature, as determined on the basis of time-resolved measurements at z = 23 cm. 17/33

18. SPIE Intern. Congress, Warsaw 2005 Experimental arrangement used for time-resolved spectroscopic studies within the PF-1000 experiment. 18/33

19. Top view of the large PF-1000 experimental chamber with side-on diagnostic ports used for optical measurements. SPIE Intern. Congress, Warsaw 2005 19/33

20. Typical traces from PF-1000 experiment: a part of the discharge current trace showing the dip (peculiarity), and correlated X-ray and neutron pulses (N1, N2). The exposition is marked by a shadowed area. 20/33

21. SPIE Intern. Congress, Warsaw 2005 Temporal changes in the deuterium- and impurity-lines emitted from high-temperature plasma within the PF-1000 facility. 21/33

22. SPIE Intern. Congress, Warsaw 2005 Optical spectra of plasma in the PF-1000 facility, as measured at short- and long-exposition for two shots under identical initial conditions. Optical spectra of plasma in the PF-1000 facility, as measured at short- and long-exposition for two shots under identical initial conditions. 22/33

23. SPIE Intern. Congress, Warsaw 2005 Fitting of spectral lines by means of the GRAMS/32 software. Approximate values of the identified D  and CuII lines are given in nm. Fitting of spectral lines by means of the GRAMS/32 software. Approximate values of the identified D  and CuII lines are given in nm. 23/33

24. SPIE Intern. Congress, Warsaw 2005 Quantitative analysis of the identified spectral lines Quantitative analysis of the identified spectral lines I max and I 0 values denote intensity in a center of the identified line and the total intensity of that taken from a NIST database, I max and I 0 values denote intensity in a center of the identified line and the total intensity of that taken from a NIST database,  is the measured Lorenz half-width of that line. 24/33

25. Temporal changes of the deuterium plasma density and of copper ions concentration in the PF-1000 experiment. SPIE Intern. Congress, Warsaw 2005 25/33

26. Optical spectra recorded with a 3-µs exposition during different phases of the PF-1000 discharge interacting with a C-Cu target (placed 15 cm from anode). SPIE Intern. Congress, Warsaw 2005 26/33

27. The first Multi-Rod Plasma Injectors (RPI) were built at the Institute for Nuclear Research in Warsaw in the late 50s. Scheme of the RPI device and RPI-IONOTRON facility of 15 kJ energy. SPIE Intern. Congress, Warsaw 2005 27/33

28. The RPI-IBIS device used for the generation of pulsed plasma-ion streams. SPIE Intern. Congress, Warsaw 2005 28/33

29. Scheme of the RPI-IBIS facility with some diagnostic equipment for spectroscopic- and corpuscular-measurements. SPIE Intern. Congress, Warsaw 2005 29/33

30. Exemplary optical spectra recorded for different operational modes of the RPI-IBIS facility, which depend on a so-called time delay of the voltage pulse in the relation to the gas puffing. SPIE Intern. Congress, Warsaw 2005 30/33

31. Average values of the electron concentration and temperature, as estimated for different operational modes of the RPI-IBIS facility. SPIE Intern. Congress, Warsaw 2005 31/33

32. Summary and conclusions 1. It was indicated that the time-integrated spectroscopic measurements can be used for estimates of plasma parameters in long-lasting stable plasma discharges only, and to investigate pulse short-living plasma one must perform time-resolved measurements with high temporal resolution. 2. This talk presented a convenient measuring setup which consists of a Mechelle ® 900 optical spectrometer equipped with a cooled CCD camera coupled with a PC and GRAMS-32 ® software, which is very useful for the identification and analysis (fitting) of the recorded spectral lines. SPIE Intern. Congress, Warsaw 2005 32/33

33. 3. Numerous spectroscopic measurements, as performed with the PF-360 and PF-1000 facilities, have been reviewed and it has been shown that the time-resolved spectroscopy is a powerful diagnostic technique for investigation of physical processes in high-temperature plasmas as well as for studies of plasma-target interactions. 4. Some spectroscopic measurements, as performed with RPI-IBIS facility, have also confirmed applicability of the time-resolved spectroscopy for basic investigation and application oriented research, e.g. material engineering. The presented results of research on dynamics of pulsed plasma streams (produced in different experimental facilities) as well as the described optical diagnostic techniques are of importance not only for plasma physics and particle accelerators, but also for research on new technology. SPIE Intern. Congress, Warsaw 2005 33/33