X-ray polarization spectroscopy to study energy transport in ultra-high intensity laser produced plasmas

Journal Article · Sat Jul 25 00:00:00 EDT 2009 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3204531· OSTI ID:21344319

Nishimura, H; Inubushi, Y; Okano, Y; Fujioka, S; Kai, T; Nakamura, T; Johzaki, T; Nagatomo, H; Mima, K ^[1]; Kawamura, T ^[2]; Batani, D; Morace, A; Redaelli, R ^[3]; Fourment, C; Santos, J ^[4]; Malka, G ^[5]; Boscheron, A ^[6]; Casner, A ^[7]; Koenig, M ^[8]

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1. Institute of Laser Engineering, Osaka University, Suita, Osaka (Japan)
2. Tokyo Institute of Technology, Yokohama, Kanagawa (Japan)
3. University of Milan, Bicocca (Italy)
4. CELIA, Universite de Bordeaux 1/CNRS/CEA, Talence (France)
5. CENBG, Universite de Bordeaux 1/CNRS-IN2P3, Gradignan (France)
6. CEA/CESTA Le BARP (France)
7. CEA-DAM Ile de France, Bruyres-le-Chatel (France)
8. LULI, Ecole Polytechnique, Palaiseau Cedex (France)

X-ray polarization spectroscopy was studied to derive directly the velocity distribution function (VDF) of hot electrons propagating in plasma created with a high intensity laser pulse. Polarization measurement was made at around 10{sup 18} W/cm{sup 2} using a laser pulse (approx10 J in approx1 ps) from Alise facility at CEA/CESTA. Chlorinated triple-layer targets were irradiated, and Cl Healpha line was observed with an x-ray polarization spectrometer. Polarization degrees were measured as a function of the target overcoat thickness, corresponding to the depth along pre-formed plasma. It is found that the polarization is weakly negative for thin coating, but becomes positive, and finally zero for thick coating. This result is consistent with predictions made with a time-dependent atomic kinetics code developed to gain an insight into the generation of polarized Cl Healpha radiation. The de-polarization on the surface is attributed to excessive bulk electron temperature and that in the deep region to elastic-scattering processes by the isotropic bulk electrons in dense region.

• OSTI ID: 21344319
• Journal Information: AIP Conference Proceedings, Vol. 1153, Issue 1; Conference: 2. international symposium on laser-driven relativistic plasmas applied to science, industry and medicine, Kyoto (Japan), 19-23 Jan 2009; Other Information: DOI: 10.1063/1.3204531; (c) 2009 American Institute of Physics; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
DISTRIBUTION FUNCTIONS
ELASTIC SCATTERING
ELECTRON TEMPERATURE
ELECTRONS
ENERGY TRANSFER
KINETICS
LASER TARGETS
LASER-PRODUCED PLASMA
PLASMA DIAGNOSTICS
POLARIZATION
TIME DEPENDENCE
VELOCITY
X-RAY SPECTROSCOPY
ELEMENTARY PARTICLES
FERMIONS
FUNCTIONS
LEPTONS
PLASMA
SCATTERING
SPECTROSCOPY
TARGETS