Two-component structure in the angular emission of a laser-produced Ta plasma

  • The particle flux produced by an obliquely incident Nd Q-switched pulse (20 ns) on a Ta target has been analysed with regard to its angular distribution resolved for both its neutral and ion components. The laser intensity has been varied in the range between about 10^10 - 10^11 W cm-2, which is appropriate for many low-irradiance applications. It is observed that, at all emission angles and for the whole range of laser intensities, the number of neutral species clearly dominates the composition of the particles. At 1.3 x 10^10 W cm-2 the total number of emitted particles is 4 x 10^14, scaling as E_L^¾ with the laser energy. While for relatively low laser energies the angular distribution shows the usual smooth cos-behaviour, an additional strong directive emission cone, superimposed upon the cos-distribution, develops if the laser energy is enhanced. Both the strength and the width strongly depend on the laser intensity. While at lower intensities a fit by a cos^n function with n ~ 10 seems appropriate, n increases to 26 at an intensity of 10^11 W cm-2 . It can be assumed that secondary energy transfer processes that are not yet fully understood are responsible for this anomalous emission.

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Verfasserangaben:Andrea Thum, Axel Rupp, Klaus Rohr
URN (Permalink):urn:nbn:de:hbz:386-kluedo-15120
Sprache der Veröffentlichung:Englisch
Jahr der Fertigstellung:1994
Jahr der Veröffentlichung:1994
Veröffentlichende Institution:Technische Universität Kaiserslautern
Beteiligte Körperschaft:Deutsche Forschungsgemeinschaft
Datum der Publikation (Server):29.12.2007
Freies Schlagwort / Tag:Plasmaexpansion
Angular distribution; Laser-produced plasma; Neodymium lasers; Plasma expansion; Tantalum
GND-Schlagwort:Festkörper; Güteschaltung; Lasererzeugtes Plasma; Neodym-YAG-Laser; Tantal; Winkelverteilung
Quelle:J. Phys. D: Appl. Phys., Vol. 27(1994), S.1791
Fachbereiche / Organisatorische Einheiten:Fachbereich Physik
DDC-Sachgruppen:5 Naturwissenschaften und Mathematik / 530 Physik
Lizenz (Deutsch):Standard gemäß KLUEDO-Leitlinien vor dem 27.05.2011