Induced m=0 instability in fast ablative capillary discharges and possible utilisation for X-ray lasers

• Autorzy: Ellwi S. , Andreic Z. , Ferri S. , Juschkin L. , Koshelev K. , Kunze H.
• Języki publikacji: EN

Abstrakty

EN

High current linear discharges confined by their own magnetic field are subject to magneto-hydrodynamic instabilities which perturb a straight plasma column. An example is the m=0 mode, which is characterised by the development of necks contracting rapidly towards the axis with the ion sound speed. Discharges through capillaries were assumed to be stable hitherto, but by cutting capillaries lengthwise after a few shots hot spot traces clearly imprinted on the inner wall of the capillary are observed. They are interpreted as marks of an m=0 instability, and this interpretation is substantiated by a series of time-gated pinhole images, which show that the hot plasma region is clearly detached from the wall at the second current maximum and concentrated on the axis thus making the development of the instability possible. The instability occurs only with a specific sample of polyacetal as wall material, and its axial wavelength increases with the length of the capillary. By modulating respectively the inner wall of the capillary the wavelength can be imposed within limits. This is exploited for a soft X-ray laser scheme based on charge exchange pumping of bare carbon ions of hot plasma streaming from the necks and colliding with cold plasma outside the neck regions. Exponential growth of the Balmer-alfa line of CVI at 18.22 nm is realised.

Słowa kluczowe

EN

Balmer-alpha of CVI; capillary discharge; charge exchange; induced instability; X-ray lasers

• Wydawca: Institute of Nuclear Chemistry and Technology
• Czasopismo: Nukleonika
• Rocznik: 2001
• Tom: Vol. 46, nr 1
• Strony: 1--3
• Opis fizyczny: Bibliogr. 7 poz., rys.

Twórcy

autor

Ellwi S.

• Institute of Experimental Physics V, Ruhr-University, 44780 Bochum, Germany, Tel.: [phone], Fax: [phone]

autor

Andreic Z.

• Institute of Experimental Physics V, Ruhr-University, 44780 Bochum, Germany Permanent address: Division of Materials Research, Rudjer Boskovic Institute, Bijenicka 54, 10000 Zagreb, Croatia

autor

Ferri S.

• Institute of Experimental Physics V, Ruhr-University, 44780 Bochum, Germany, Tel.: [phone], Fax: [phone]

autor

Juschkin L.

• Institute of Experimental Physics V, Ruhr-University, 44780 Bochum, Germany, Tel.: [phone], Fax: [phone]

autor

Koshelev K.

• Institute for Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow region, 142190 Russia

autor

Kunze H.

• Institute of Experimental Physics V, Ruhr-University, 44780 Bochum, Germany, Tel.: [phone], Fax: [phone]

Bibliografia

• 1. Haines MG, Coppins M (1991) Universal diagram for regimes of Z-pinch stability. Phys Rev Lett 66:1462–1465
• 2. Koshelev KN, Kunze H-J (1997) Population inversion in a discharge plasma with neck-type instabilities. Quantum Electron 27:164–167
• 3. Kunze H-J, Koshelev KN, Steden C, Uskov D, Wieschebrink HT (1994) Lasing mechanism in a capillary discharge. Phys Lett A 193:183–187
• 4. Schefel J, Coppins M (1993) Reconsideration of the m=0 Z-pinch stability. Nucl Fusion 33:101–115
• 5. Sethian JD, Robson AE, Gerber KA, DeSilva AW (1987) Enhanced stability and neutron production in a dense Z-pinch plasma formed from a frozen deuterium fiber. Phys Rev Lett 59:892–895
• 6. Vikhrev VV, Ivanov VV, Rozanova GA (1993) Development of sausage-type instability in a Z-pinch plasma column. Nucl Fusion 33:311–321
• 7. Yan’kov VV (1991) Z-pinches. Sov J Plasma Phys 17:305–311