Die Entwicklung von TEA-CO2_{2}-Lasern und deren Einsatz in der Plasmaphsik

Es soll über gepulste CO$_{2}$-Laser hoher Leistung berichtet werden, ein Lasertyp, der vor allem unter dem Namen TEA-CO$_{2}$-Laser bekannt worden ist. Die Bezeichnung TEA charakterisiert die Entladungsgeometrie und den Gasdruck, sie bedeutet "transversely excited atmospheric pressure". Mit diesen Lasern gelang es zum ersten Mal im mittleren Infrarot bei 10,6/u Wellenlänge Leistungen bis in den Gigawattbereich zu erzeugen; und man erwartet von diesem Laser Leistungen bis zu Terawatt bei Impulsenergien von mehr als einem Kilojoule. Ein besonderer Vorteil aller CO$_{2}$-Laser ist der hohe Wirkungsgrad, der über 10% erreichen kann

Faraday rotation measurement of trapped magnetic fields in a thetapinch plasma

Using a 3.39-$\mu$ He-Ne laser, trapped fields of -4 to +8 kG were measured in a 45-kG driving field ($\beta$ > 0.97) when no bias field was applied. With antiparallel bias field no trapped field reversal was observed at high densities

Bestimmung von Temperatur und Dichte eines Gleitfunkens aus der Bremsstrahlung im Infrarot

The absolute intensity of a vacuum sliding spark (length 2-10 cm, half cycle 0,8 $\mu$sec) has been measured in the spectral region between 0,4 and 3 $\mu$. From the long wavelength radiation emitted from an optically thick layer, one gets the temperature, fromthe short wavelength radiation emitted from an optically thin layer, one obtains the density. Using polyethylene as an insulator we reached a temperature of 4 · 10$^{5}$ °K at electron densities of 8 · 10$^{18}$ cm$^{-3}$ and current densities of 1.2 · 10$^{6}$ A/cm$^{2}$. The temporal development of temperature and density has been determined. The maximum intensity at $\lambda=0.43 \mu$ was found to be 5 • 10$^{4}$ (7 · 10$^{10}$ W/cm$^{3}$ ster) as large as that of the positive crater of a properly driven carbon arc. At $\lambda= 3 \mu$ this same parameter turned out to be 300 times as large (5 · 10$^{7}$ W/cm$^{3}$ ster)

Spectroscopic measurements of the ion temperature profile in front of a limiter in Textor-94

Ion temperatures have been measured in front of a limiter in TEXTOR-94 under various plasma conditions by means of the Doppler broadening of the C5+ line (lambda = 529 nm), which is excited by charge exchange processes with hydrogen (deuterium) atoms recycled at the limiter surface. The ion temperatures have been compared with electron temperatures measured by atomic beam techniques. It has been found that the ion temperatures are considerably larger than those of the electrons. In the scrape-off layer (SOL) the ratio between the ion and electron temperatures (T-i /T-e) can reach values of up to three at low plasma densities, but this ratio decreases with increasing density. The SOL e-folding length of the ion temperature is much larger than that of the electron temperature. The influence of the test limiter position r(L) on the ion temperature measurements has been investigated but found to be of no significant importance

Bestimmung der Speziesverteilung H+^{+}, H2+^{+}_{2} und H3+^{+}_{3} in der Ionenquelle für die Neutralteilchen-Injektoren an Textor

The ion species fractions H$^{+}$, H$^{+}_{2}$ and H$^{+}_{3}$ in the extracted beam of an ion source for neutral beam injection are detennined. Optical rneasureruents are obtained frorn a grating spectrometer using Dopplershifted H$_{\alpha}$ -light of the extracted beam and are compared to measurements with a magnetic spectrometer at the end of the beam line. The plasma source is a bucket source (modified JET-PINI) with a multiple magnetic field in checkerboard arrangement. The measurernents were performed on the multimegawatt beam line of the IPP NI - testfacility at KFA Jülich. The species fractions obtained for beams at 50 kV, 85 A, 4.25 MW are 63.8 : 24.5 : 11.7% (H$^{+}$ : H$^{+}_{2}$ : H$^{+}_{3}$). Measurements over the beam pulse length of 2.6 sec show no significant variation of the extracted species mix with pulse length

Bestimmung der Speziesverteilung H+^{+}, H2+^{+}_{2} und H3+^{+}_{3} in der Ionenquelle für die Neutralteilchen-Injektoren an Textor

The ion species fractions H$^{+}$, H$^{+}_{2}$ and H$^{+}_{3}$ in the extracted beam of an ion source for neutral beam injection are detennined. Optical rneasureruents are obtained frorn a grating spectrometer using Dopplershifted H$_{\alpha}$ -light of the extracted beam and are compared to measurements with a magnetic spectrometer at the end of the beam line. The plasma source is a bucket source (modified JET-PINI) with a multiple magnetic field in checkerboard arrangement. The measurernents were performed on the multimegawatt beam line of the IPP NI - testfacility at KFA Jülich. The species fractions obtained for beams at 50 kV, 85 A, 4.25 MW are 63.8 : 24.5 : 11.7% (H$^{+}$ : H$^{+}_{2}$ : H$^{+}_{3}$). Measurements over the beam pulse length of 2.6 sec show no significant variation of the extracted species mix with pulse length

Molecular spectroscopy in TEXTOR

A progress report about 15 years molecular spectroscopy on TEXTOR is given. Spectra of CH/H, BH/D, SiH/D, C-2, CO and H-2/D-2 are discussed for plasma boundary conditions in a fusion device and the behaviour of these constituents for varying plasma and surface conditions are presented