Diagnosis of warm dense conditions in foil targets heated by intense femtosecond laser pulses using Kα imaging spectroscopy

• Published in: Optics express Vol. 26; no. 5; pp. 6294 - 6301
• Main Authors: Bae, L J, Zastrau, U, Chung, H-K, Bernstein, A C, Cho, M S, Dyer, G M, Galtier, E, He, Z-H, Heimann, P A, Kang, G B, Kim, M, Kim, Y H, Lee, H J, Lee, J W, Nagler, B, Thomas, A G R, Cho, B I
• Format: Journal Article
• Language: English
• Published: United States Optical Society of America (OSA) 05.03.2018
• Subjects: MATERIALS SCIENCE; OTHER INSTRUMENTATION
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.26.006294

Warm dense conditions in titanium foils irradiated with intense femtosecond laser pulses are diagnosed using an x-ray imaging spectroscopy technique. The line shapes of radially resolved titanium Kα spectra are measured with a toroidally bent GaAs crystal and an x-ray charge-coupled device. Measured spectra are compared with the K-shell emissions modeled using an atomic kinetics - spectroscopy simulation code. Kα line shapes are strongly affected by warm (5-40 eV) bulk electron temperatures and imply multiple temperature distributions in the targets. The spatial distribution of temperature is dependent on the target thickness, and a thin target shows an advantage to generate uniform warm dense conditions in a large area.