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VOLUME 62 (1995) | ISSUE 10 |
PAGE 775
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Measurement of the electron temperature distribution in a Z pinch by the laser absorption method
Sarkisov G. S. , Etlicher B.
A new method is proposed for measuring the electron temperature in the interior region of a Ζ pinch. The method is based on laser probing of the plasma with simultaneous measurement of the absorption and interference phase shift profiles of the probe radiation inside the Ζ pinch. It is shown that the opaque region which appears in the pinch in laser-probing experiments is related to the absorption of radiation and not to the refraction of the radiation by transverse gradients of the electron density (as previously believed). The refraction of the laser radiation does not exceed the angular aperture of the recording optics and cannot influence the formation of the opaque region in the image of the central part of the pinch. It is shown that the laser radiation transmitted through the Ζ pinch has a high degree of coherence, which makes it possible to perform interferometry of the absorption region. In experiments with Ζ pinches formed by exploding a 20-,um-aluminum wire with a ~250-kA, 50-ns current pulse, electron densities and electron temperatures —1.4X1020 cm3 and —530 eV, respectively, were produced at the neck of the pinch. © 1995 American Institute of Physics.
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