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Title: Inference of the electron temperature in inertial confinement fusion implosions from the hard X-ray spectral continuum

Abstract

Using the free-free continuum self-emission spectrum at photon energies above 15 keV is one of the most promising concepts for assessing the electron temperature in inertial confinement fusion (ICF) experiments. However, these photons are due to suprathermal electrons whose mean free path is much larger than the thermal one, making their distribution deviate from Maxwellian in a finite-size hotspot. Here, the first study of the free-free X-ray emission from an ICF implosion is conducted, accounting for the kinetic modifications to the electron distribution. These modifications are found to result in qualitatively new features in the hard X-ray spectral continuum. Finally, inference of the electron temperature as if the emitting electrons are Maxwellian is shown to give a lower value than the actual one.

Authors:
 [1];  [2];  [1];  [3];  [3];  [3];  [3];  [3];  [3];  [1];  [1];  [1];  [1];  [2];  [2];  [2];  [2];  [2]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE; LANL Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1477695
Alternate Identifier(s):
OSTI ID: 1469404
Report Number(s):
LA-UR-17-28158
Journal ID: ISSN 0863-1042
Grant/Contract Number:  
AC52-06NA25396
Resource Type:
Accepted Manuscript
Journal Name:
Contributions to Plasma Physics
Additional Journal Information:
Journal Name: Contributions to Plasma Physics; Journal ID: ISSN 0863-1042
Publisher:
Wiley
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; high-energy-density; inertial confinement; x-ray diagnostic

Citation Formats

Kagan, Grigory, Landen, O. L., Svyatskiy, D., Sio, H., Kabadi, N. V., Simpson, R. A., Gatu Johnson, M., Frenje, J. A., Petrasso, R. D., Shah, R. C., Joshi, T. R., Hakel, P., Weber, T. E., Rinderknecht, H. G., Thorn, D., Schneider, M., Bradley, D., and Kilkenny, J. Inference of the electron temperature in inertial confinement fusion implosions from the hard X-ray spectral continuum. United States: N. p., 2018. Web. doi:10.1002/ctpp.201800078.
Kagan, Grigory, Landen, O. L., Svyatskiy, D., Sio, H., Kabadi, N. V., Simpson, R. A., Gatu Johnson, M., Frenje, J. A., Petrasso, R. D., Shah, R. C., Joshi, T. R., Hakel, P., Weber, T. E., Rinderknecht, H. G., Thorn, D., Schneider, M., Bradley, D., & Kilkenny, J. Inference of the electron temperature in inertial confinement fusion implosions from the hard X-ray spectral continuum. United States. doi:10.1002/ctpp.201800078.
Kagan, Grigory, Landen, O. L., Svyatskiy, D., Sio, H., Kabadi, N. V., Simpson, R. A., Gatu Johnson, M., Frenje, J. A., Petrasso, R. D., Shah, R. C., Joshi, T. R., Hakel, P., Weber, T. E., Rinderknecht, H. G., Thorn, D., Schneider, M., Bradley, D., and Kilkenny, J. Mon . "Inference of the electron temperature in inertial confinement fusion implosions from the hard X-ray spectral continuum". United States. doi:10.1002/ctpp.201800078. https://www.osti.gov/servlets/purl/1477695.
@article{osti_1477695,
title = {Inference of the electron temperature in inertial confinement fusion implosions from the hard X-ray spectral continuum},
author = {Kagan, Grigory and Landen, O. L. and Svyatskiy, D. and Sio, H. and Kabadi, N. V. and Simpson, R. A. and Gatu Johnson, M. and Frenje, J. A. and Petrasso, R. D. and Shah, R. C. and Joshi, T. R. and Hakel, P. and Weber, T. E. and Rinderknecht, H. G. and Thorn, D. and Schneider, M. and Bradley, D. and Kilkenny, J.},
abstractNote = {Using the free-free continuum self-emission spectrum at photon energies above 15 keV is one of the most promising concepts for assessing the electron temperature in inertial confinement fusion (ICF) experiments. However, these photons are due to suprathermal electrons whose mean free path is much larger than the thermal one, making their distribution deviate from Maxwellian in a finite-size hotspot. Here, the first study of the free-free X-ray emission from an ICF implosion is conducted, accounting for the kinetic modifications to the electron distribution. These modifications are found to result in qualitatively new features in the hard X-ray spectral continuum. Finally, inference of the electron temperature as if the emitting electrons are Maxwellian is shown to give a lower value than the actual one.},
doi = {10.1002/ctpp.201800078},
journal = {Contributions to Plasma Physics},
number = ,
volume = ,
place = {United States},
year = {2018},
month = {9}
}

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