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Title: Observation of modulations in Lyman-{alpha} line profiles of multicharged ions in clusters irradiated by femtosecond laser pulses: Effect of a dynamic electric field

Abstract

Profiles of the Ly{sub {alpha}} line of O VIII ions in N{sub 2}O clusters irradiated by fs laser pulses (laser flux up to 4x10{sup 17} W/cm{sup 2}) were recorded. The features (peaks and dips) in the Ly{sub {alpha}} O VIII line profiles were observed. The experimental spectra were simulated theoretically assuming that strong oscillating electric fields are generated in the cluster plasma. We showed that allowing for oscillating electric fields of the amplitude E{sub 0}{approx}(0.5-1.0)x10{sup 9} V/cm and frequency {omega}{approx}(0.7-2.4)x10{sup 15} s{sup -1} leads to spectral features in the theoretical profiles of the Ly{sub {alpha}} O VIII line that are similar to the features observed experimentally. Possible mechanisms responsible for the generation of strong oscillating electric fields in the cluster plasma are discussed.

Authors:
 [1];  [2]; ; ; ;  [3]; ;  [4]
  1. A.M. Prokhorov Institute of General Physics, Russian Academy of Sciences, Vavilov Str. 38, Moscow 119991 (Russian Federation)
  2. (Russian Federation)
  3. Multicharged Ions Spectra Data Center of VNIIFTRI, Mendeleevo, Moscow Region, 141570 (Russian Federation)
  4. Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States)
Publication Date:
OSTI Identifier:
20786727
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 73; Journal Issue: 1; Other Information: DOI: 10.1103/PhysRevA.73.013203; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; AMPLITUDES; ELECTRIC FIELDS; EMISSION SPECTRA; IRRADIATION; LASER-PRODUCED PLASMA; MODULATION; MOLECULAR CLUSTERS; MULTICHARGED IONS; NITROUS OXIDE; OXYGEN IONS; PHOTON-MOLECULE COLLISIONS; PLASMA PRODUCTION; PULSES; STARK EFFECT; X-RAY SPECTRA

Citation Formats

Gavrilenko, V. P., Center for Surface and Vacuum Research, Novatorov Street 40-1, Moscow 119421, Faenov, A. Ya., Magunov, A. I., Pikuz, T. A., Skobelev, I. Yu., Kim, K. Y., and Milchberg, H. M. Observation of modulations in Lyman-{alpha} line profiles of multicharged ions in clusters irradiated by femtosecond laser pulses: Effect of a dynamic electric field. United States: N. p., 2006. Web. doi:10.1103/PHYSREVA.73.0.
Gavrilenko, V. P., Center for Surface and Vacuum Research, Novatorov Street 40-1, Moscow 119421, Faenov, A. Ya., Magunov, A. I., Pikuz, T. A., Skobelev, I. Yu., Kim, K. Y., & Milchberg, H. M. Observation of modulations in Lyman-{alpha} line profiles of multicharged ions in clusters irradiated by femtosecond laser pulses: Effect of a dynamic electric field. United States. doi:10.1103/PHYSREVA.73.0.
Gavrilenko, V. P., Center for Surface and Vacuum Research, Novatorov Street 40-1, Moscow 119421, Faenov, A. Ya., Magunov, A. I., Pikuz, T. A., Skobelev, I. Yu., Kim, K. Y., and Milchberg, H. M. Sun . "Observation of modulations in Lyman-{alpha} line profiles of multicharged ions in clusters irradiated by femtosecond laser pulses: Effect of a dynamic electric field". United States. doi:10.1103/PHYSREVA.73.0.
@article{osti_20786727,
title = {Observation of modulations in Lyman-{alpha} line profiles of multicharged ions in clusters irradiated by femtosecond laser pulses: Effect of a dynamic electric field},
author = {Gavrilenko, V. P. and Center for Surface and Vacuum Research, Novatorov Street 40-1, Moscow 119421 and Faenov, A. Ya. and Magunov, A. I. and Pikuz, T. A. and Skobelev, I. Yu. and Kim, K. Y. and Milchberg, H. M.},
abstractNote = {Profiles of the Ly{sub {alpha}} line of O VIII ions in N{sub 2}O clusters irradiated by fs laser pulses (laser flux up to 4x10{sup 17} W/cm{sup 2}) were recorded. The features (peaks and dips) in the Ly{sub {alpha}} O VIII line profiles were observed. The experimental spectra were simulated theoretically assuming that strong oscillating electric fields are generated in the cluster plasma. We showed that allowing for oscillating electric fields of the amplitude E{sub 0}{approx}(0.5-1.0)x10{sup 9} V/cm and frequency {omega}{approx}(0.7-2.4)x10{sup 15} s{sup -1} leads to spectral features in the theoretical profiles of the Ly{sub {alpha}} O VIII line that are similar to the features observed experimentally. Possible mechanisms responsible for the generation of strong oscillating electric fields in the cluster plasma are discussed.},
doi = {10.1103/PHYSREVA.73.0},
journal = {Physical Review. A},
number = 1,
volume = 73,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}
  • Profiles of the Ly{alpha} line of O VIII ions in N{sub 2}O clusters irradiated by femtosecond laser pulses (laser flux up to 4x10{sup 17} W/cm{sup 2}) were recorded. The features (peaks and dips) in the Ly{alpha} O VIII line profiles were observed evidencing the presence of intense plasma oscillations with an amplitude of the electric field E0 {approx} (0.5-1.0) x 10{sup 9} V/cm and a frequency {omega} {approx} (0.7-2.4) x 10{sup 15} s{sup -1}.
  • A study is made of the ultra-short laser pulse irradiation of Ar cluster targets. Experiments have been performed with large cluster sizes and using very high laser contrasts, which have allowed clear and unambiguous observation of exotic inner-shell transitions in near-neutral Ar ions. The interaction of the main laser pulse with the unperturbed target is a necessary requirement for observing these lines. Our measurements are supported by kinetics calculations in which a very detailed atomic model is used. The calculations predict all of the spectral features found experimentally, and support the notion that the X-ray emission arises from many ionmore » stages of the Ar plasma, from near-neutral through He-like ions, and from a range of plasma temperatures and densities. Differences between X-ray argon clusters excited at the laser-cluster and laser-droplet interactions have been analyzed. X-ray spectral methods have been proposed to determine the parameters of the plasma formed at the early stages of its evolution. It has been shown that the spectra of hollow ions are the most informative in the first moments of the heating of a cluster, whereas the diagnostics of the late stages can be performed using the conventional lines of multicharged ions.« less
  • Energy distributions of ions emitted from argon clusters (up to 12 800 atoms/cluster) Coulomb-exploded with an intense femtosecond laser have been experimentally studied. Under the laser intensity of 2x10{sup 16} W/cm{sup 2}, the ions of >15 keV are anisotropically emitted, while those lower than 15 keV tend to be isotropic. The argon ions of charge state up to Ar{sup 14+} were generated, and their high charge state is more than expected by the barrier suppression ionization model. The yield and maximum energy of Ar{sup 8+}-Ar{sup 14+} ions depend on laser polarization direction, while those of Ar{sup +}-Ar{sup 7+} are muchmore » less sensitive to the laser polarization. The present results suggests that high-charge-state and anisotropically emitted ions are produced by impact ionization of electrons that are produced by optical field ionization with the intense laser.« less
  • X-ray line emission from 2{ell} - n{ell}{prime} transitions in Ne-like Kr and nearby ions has been observed from {approx} 1 {micro}m Kr clusters irradiated by fs-scale laser pulses at the JAERI facility in Kyoto, Japan. The incident laser intensity reached 10{sup 19} W/cm{sup 2}, with pulse energies from 50 to 300 mJ and pulse durations from 30 to 500 fs. The dependence of the x-ray spectral features and intensity on the incident laser intensity is rather weak, indicating that the 1 - 2 ps cluster lifetimes limit the number of ions beyond Ne-like Kr that can be produced by collisionalmore » ionization. Lines from F- to Al-like Kr emitted from the cluster plasmas have been identified using data from the relativistic multiconfiguration atomic structure code FAC. A collisional-radiative model based on this data has been constructed and used to determine that the cluster plasma has electron densities near 10{sup 22} cm{sup -3}, temperatures of a few hundred eV and hot electron fractions of a few percent.« less
  • X-ray line emission from 2l-nl{sup '} transitions in Ne-like Kr and nearby ions has been observed from {approx_equal}1 {mu}m Kr clusters irradiated by fs-scale laser pulses at the JAERI facility in Kyoto, Japan. The incident laser intensity reached 10{sup 19} W/cm{sup 2}, with pulse energies from 50 to 300 mJ and pulse durations from 30 to 500 fs. The dependence of the x-ray spectral features and intensity on the incident laser intensity is rather weak, indicating that the 1-2 ps cluster lifetimes limit the number of ions beyond Ne-like Kr that can be produced by collisional ionization. Lines from F-more » to Al-like Kr emitted from the cluster plasmas have been identified using data from the relativistic multiconfiguration flexible atomic code. A collisional-radiative model based on these data has been constructed and used to determine that the cluster plasma has electron densities near 10{sup 22} cm{sup -3}, temperatures of a few hundred eV, and hot electron fractions of a few percent.« less