Stimulated Brillouin backscattering from underdense expanding plasmas in a regime of strong filamentation
Authors: Giulietti A., Macchi A., Schifano E., Biancalana V., Danson C., Giulietti D., Gizzi LA., Willi O.
Autors Affiliation: CNR, Ist Fis Atom & Mol, I-56127 Pisa, Italy;
Scuola Normale Super Pisa, Pisa, Italy;
Univ Pisa, Ist Nazl Fis Mat, Sez A, Pisa, Italy;
Univ Siena, Dipartimento Fis, I-53100 Siena, Italy;
Rutherford Appleton Lab, Cent Laser Facil, Chilton, England;
Univ Pisa, Dipartimento Fis, Pisa, Italy;
Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London, England
Abstract: Stimulated Brillouin backscattering (B-SBS) from delayed interaction with a preformed, long scale-length expanding plasma was experimentally investigated in a regime favorable to strong self-focusing (SF) and filamentation. An extremely low backscattering reflectivity (of the order of 10(-4)) was measured and anomalous time-resolved spectra were observed. Spectral and temporal features of the reflectivity suggest a strong effect of SF on B-SBS: In the early phase of the interaction SF lowers the B-SBS threshold and possibly leads to rapid saturation, while in the late phase there is a substantial decoupling of the SBS active regions from the plasma bulk due to their motion towards the laser beam. This motion is attributed to a moving focus effect driven by ponderomotive SF.
Journal/Review: PHYSICAL REVIEW E
Volume: 59 (1) Pages from: 1038 to: 1046
KeyWords: laser hot-spots; scattering; light; propagation; wavesDOI: 10.1103/PhysRevE.59.1038Citations: 22data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2021-12-05References taken from IsiWeb of Knowledge: (subscribers only)Connecting to view paper tab on IsiWeb: Click hereConnecting to view citations from IsiWeb: Click here