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Title: An efficient, selective collisional ejection mechanism for inner-shell population inversion in laser-driven plasmas

Abstract

A theoretical analysis of laser-driven collisional ejection of inner-shell electrons is presented to explain the previously observed anomalous kilovolt L-shell x-ray emission spectra from atomic Xe cluster targets excited by intense sub-picosecond 248nrn ultraviolet radiation. For incident ponderomotively-driven electrons photoionized by strong above threshold ionization, the collisional ejection mechanism is shown to be highly l-state and significantly n-state (i.e. radially) selective for time periods shorter than the collisional dephasing time of the photoionized electronic wavefunction. The resulting preference for the collisional ejection of 2p electrons by an ionized 4p state produces the measured anomalous Xe(L) emission which contains direct evidence for (i) the generation of Xe{sup 27+}(2p{sup 5}3d{sup 10}) and Xe{sup 28+}(2p{sup 5}3d{sup 9}) ions exhibiting inner-shell population inversion and (ii) a coherent correlated electron state collision responsible for the production of double 2p vacancies. For longer time periods, the selectivity of this coherent impact ionization mechanism is rapidly reduced by the combined effects of intrinsic quantum mechanical spreading and dephasing--in agreement with the experimentally observed and extremely strong {minus}{lambda}{sup {minus}6} pump-laser wavelength dependence of the efficiency of inner-shell (2p) vacancy production in Xe clusters excited in underdense plasmas.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Sandia National Labs., Albuquerque, NM (US); Sandia National Labs., Livermore, CA (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
756440
Report Number(s):
SAND2000-1445J
TRN: AH200022%%172
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Journal Article
Journal Name:
Journal of Physics B: Atomic Molecular and Optical Physics
Additional Journal Information:
Other Information: Submitted to Journal of Physics B: Atomic Molecular and Optical Physics; PBD: 7 Jun 2000
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; X-RAY LASERS; XENON; EMISSION SPECTRA; PHOTOIONIZATION; POPULATION INVERSION; LASER-PRODUCED PLASMA; X RADIATION

Citation Formats

SCHROEDER,W. ANDREAS, NELSON,THOMAS R., BORISOV,A.B., LONGWORTH,J.W., BOYER,K., and RHODES,C.K. An efficient, selective collisional ejection mechanism for inner-shell population inversion in laser-driven plasmas. United States: N. p., 2000. Web.
SCHROEDER,W. ANDREAS, NELSON,THOMAS R., BORISOV,A.B., LONGWORTH,J.W., BOYER,K., & RHODES,C.K. An efficient, selective collisional ejection mechanism for inner-shell population inversion in laser-driven plasmas. United States.
SCHROEDER,W. ANDREAS, NELSON,THOMAS R., BORISOV,A.B., LONGWORTH,J.W., BOYER,K., and RHODES,C.K. Wed . "An efficient, selective collisional ejection mechanism for inner-shell population inversion in laser-driven plasmas". United States. https://www.osti.gov/servlets/purl/756440.
@article{osti_756440,
title = {An efficient, selective collisional ejection mechanism for inner-shell population inversion in laser-driven plasmas},
author = {SCHROEDER,W. ANDREAS and NELSON,THOMAS R. and BORISOV,A.B. and LONGWORTH,J.W. and BOYER,K. and RHODES,C.K.},
abstractNote = {A theoretical analysis of laser-driven collisional ejection of inner-shell electrons is presented to explain the previously observed anomalous kilovolt L-shell x-ray emission spectra from atomic Xe cluster targets excited by intense sub-picosecond 248nrn ultraviolet radiation. For incident ponderomotively-driven electrons photoionized by strong above threshold ionization, the collisional ejection mechanism is shown to be highly l-state and significantly n-state (i.e. radially) selective for time periods shorter than the collisional dephasing time of the photoionized electronic wavefunction. The resulting preference for the collisional ejection of 2p electrons by an ionized 4p state produces the measured anomalous Xe(L) emission which contains direct evidence for (i) the generation of Xe{sup 27+}(2p{sup 5}3d{sup 10}) and Xe{sup 28+}(2p{sup 5}3d{sup 9}) ions exhibiting inner-shell population inversion and (ii) a coherent correlated electron state collision responsible for the production of double 2p vacancies. For longer time periods, the selectivity of this coherent impact ionization mechanism is rapidly reduced by the combined effects of intrinsic quantum mechanical spreading and dephasing--in agreement with the experimentally observed and extremely strong {minus}{lambda}{sup {minus}6} pump-laser wavelength dependence of the efficiency of inner-shell (2p) vacancy production in Xe clusters excited in underdense plasmas.},
doi = {},
journal = {Journal of Physics B: Atomic Molecular and Optical Physics},
number = ,
volume = ,
place = {United States},
year = {2000},
month = {6}
}