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Title: Measurements of hot-electron temperature in laser-irradiated plasmas

In a recently published work 1–3 we reported on measuring the total energy of hot electrons produced by the interaction of a nanosecond laser with planar CH-coated molybdenum targets, using the Mo K α emission. The temperature of the hot electrons in that work was determined by the high-energy bremsstrahlung [hard x-ray (HXR)] spectrum measured by a three-channel fluorescence-photomultiplier detector (HXRD). In the present work, we replaced the HXRD with a nine-channel image-plate (IP)–based detector (HXIP). For the same conditions (irradiance of the order of 10 14 W/cm 2; 2-ns pulses) the measured temperatures are consistently lower than those measured by the HXRD (by a factor ~1.5 to 1.7). In addition, we supplemented this measurement with three experiments that measure the hot-electron temperature using K α line-intensity ratios from high-Z target layers, independent of the HXR emission. These experiments yielded temperatures that were consistent with those measured by the HXIP. We showed that the thermal x-ray radiation must be included in the derivation of total energy in hot electrons (E hot), and that this makes E hot only weakly dependent on hot-electron temperature. For a given x-ray emission in inertial confinement fusion compression experiments, this result would lead to amore » higher total energy in hot electrons, but the preheat of the compressed fuel may be lower because of the reduced hot-electron range.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Univ. of Rochester, Rochester, NY (United States)
Publication Date:
Grant/Contract Number:
NA0001944
Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 10; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Research Org:
Univ. of Rochester, Rochester, NY (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
OSTI Identifier:
1330098
Alternate Identifier(s):
OSTI ID: 1330118

Solodov, A. A., Yaakobi, B., Edgell, D. H., Follett, R. K., Myatt, J. F., Sorce, C., and Froula, D. H.. Measurements of hot-electron temperature in laser-irradiated plasmas. United States: N. p., Web. doi:10.1063/1.4965905.
Solodov, A. A., Yaakobi, B., Edgell, D. H., Follett, R. K., Myatt, J. F., Sorce, C., & Froula, D. H.. Measurements of hot-electron temperature in laser-irradiated plasmas. United States. doi:10.1063/1.4965905.
Solodov, A. A., Yaakobi, B., Edgell, D. H., Follett, R. K., Myatt, J. F., Sorce, C., and Froula, D. H.. 2016. "Measurements of hot-electron temperature in laser-irradiated plasmas". United States. doi:10.1063/1.4965905. https://www.osti.gov/servlets/purl/1330098.
@article{osti_1330098,
title = {Measurements of hot-electron temperature in laser-irradiated plasmas},
author = {Solodov, A. A. and Yaakobi, B. and Edgell, D. H. and Follett, R. K. and Myatt, J. F. and Sorce, C. and Froula, D. H.},
abstractNote = {In a recently published work1–3 we reported on measuring the total energy of hot electrons produced by the interaction of a nanosecond laser with planar CH-coated molybdenum targets, using the Mo Kα emission. The temperature of the hot electrons in that work was determined by the high-energy bremsstrahlung [hard x-ray (HXR)] spectrum measured by a three-channel fluorescence-photomultiplier detector (HXRD). In the present work, we replaced the HXRD with a nine-channel image-plate (IP)–based detector (HXIP). For the same conditions (irradiance of the order of 1014 W/cm2; 2-ns pulses) the measured temperatures are consistently lower than those measured by the HXRD (by a factor ~1.5 to 1.7). In addition, we supplemented this measurement with three experiments that measure the hot-electron temperature using Kα line-intensity ratios from high-Z target layers, independent of the HXR emission. These experiments yielded temperatures that were consistent with those measured by the HXIP. We showed that the thermal x-ray radiation must be included in the derivation of total energy in hot electrons (Ehot), and that this makes Ehot only weakly dependent on hot-electron temperature. For a given x-ray emission in inertial confinement fusion compression experiments, this result would lead to a higher total energy in hot electrons, but the preheat of the compressed fuel may be lower because of the reduced hot-electron range.},
doi = {10.1063/1.4965905},
journal = {Physics of Plasmas},
number = 10,
volume = 23,
place = {United States},
year = {2016},
month = {10}
}