Laser induced Coulomb explosion and stimulated Raman scattering in cluster plasmas

Journal Article · Mon Oct 15 04:00:00 EDT 2007 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2773706· OSTI ID:21062032

Tiwari, Pawan K; Mok, Chinook; Ryu, Chang-Mo ^[1]

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1. Department of Physics, POSTECH, Pohang 790-784 (Korea, Republic of)

Laser-driven Coulomb explosion can induce stimulated Raman scattering in cluster-embedded plasmas. The propagation and scattering of electromagnetic waves have been studied to show that Coulombic expansion of atomic clusters significantly modifies the scattering properties. When the cluster plasma collision is negligible, the cutoff frequency occurs due to the resonance, and this cutoff frequency is lowered as the cluster size increases. On the other hand, when there are collisions, the electron-ion collisions inhibit cluster electrons from absorbing laser energy resonantly, in which case the electromagnetic wave dispersion relation is not much affected by the presence of the cluster. Enhancement in the resonance absorption of laser energy is achieved when laser frequency becomes inversely proportional to the cubic root of the normalized cluster radius. The expansion of a dense cluster into the ambient plasma density is shown to accompany a swift decrease in the plasma wave frequency. The variation of the growth rate of the Raman backscattered wave with respect to the wave number, plasma density, and sizes of the clusters shows that, in a high-density cluster plasma, only long-wavelength modes survive until the end of the cluster expansion. The short wave scattering mode, which initially grows faster, quickly damps out in the early phase of the expansion.

• OSTI ID: 21062032
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 10 Vol. 14; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ATOMIC CLUSTERS
CLUSTER EXPANSION
DENSITY
DISPERSION RELATIONS
ELECTROMAGNETIC RADIATION
ELECTRON-ION COLLISIONS
ELECTRONS
EXPANSION
EXPLOSIONS
LASERS
LIGHT TRANSMISSION
PLASMA
PLASMA DENSITY
RAMAN EFFECT
RESONANCE ABSORPTION
SCATTERING