TY  - UNPD
A1  - Thum, Andrea
A1  - Rupp, Axel
A1  - Rohr, Klaus
T1  - Two-component structure in the angular emission of a laser-produced Ta plasma
N2  - 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.
KW  - Lasererzeugtes Plasma
KW  - Festkörper
KW  - Tantal
KW  - Neodym-YAG-Laser
KW  - Güteschaltung
KW  - Winkelverteilung
KW  - Plasmaexpansion
KW  - Laser-produced plasma
KW  - Tantalum
KW  - Neodymium lasers
KW  - Plasma expansion
KW  - Angular distribution
Y1  - 1994
UR  - https://kluedo.ub.uni-kl.de/frontdoor/index/index/docId/1919
UR  - https://nbn-resolving.org/urn:nbn:de:hbz:386-kluedo-15120
ER  -