Bright picosecond x-rays from intense sub-picosecond laser-plasma interactions

Journal Article · Mon May 01 04:00:00 EDT 1995 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.47940· OSTI ID:21153887

Maksimchuk, A; Workman, J; Liu, X; Ellenberger, U; Coe, S; Chien, C -Y; Umstadter, D ^[1]

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1. Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, MI 48109-2099 (United States)

Short-pulse, high-intensity laser-plasma interactions are investigated experimentally with temporally and spectrally resolved soft x-ray diagnostics. The emitted x-ray spectra from solid targets of various Z are characterized for a range of laser intensities (I<5x10{sup 17} W/cm{sup 2}) and pulse widths ({eta}{approx}400 fs). With low contrast (10{sup 5}), the x-ray spectrum in the {lambda}=40-100 A spectral region is dominated by line emission, and the x-ray pulse duration is found to be long, {tau}x > or approx.100 ps, characteristic of a long-scale-length, low-density plasma. Bright, picosecond, continuum emission, characteristic of a short-scalelength, high-density plasma, is produced only when a high laser contrast (10{sup 10}) is used. It is demonstrated experimentally that the pulsewidth of laser-produced x-ray radiation may be varied down to the picosecond time-scale by adjusting the incident ultrashort-pulse laser flux. This controls the peak electron temperature relative to the ionization potential, corresponding to the emitted x-ray photon energy of interest. The results are found to be consistent with the predictions of a hydrodynamics code coupled to an average atom model only if non-local thermodynamic equilibrium (NLTE) is assumed.

• OSTI ID: 21153887
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 332; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BEAM-PLASMA SYSTEMS
ELECTRON TEMPERATURE
HYDRODYNAMICS
IONIZATION POTENTIAL
LASER RADIATION
LASERS
PHOTON EMISSION
PLASMA
PLASMA DENSITY
PLASMA DIAGNOSTICS
PULSES
SOFT X RADIATION
X-RAY SPECTRA