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Title: Design of laboratory experiments to study photoionization fronts driven by thermal sources

This study analyzes the requirements of a photoionization-front experiment that could be driven in the laboratory, using thermal sources to produce the necessary flux of ionizing photons. It reports several associated conclusions. Such experiments will need to employ the largest available facilities, capable of delivering many kJ to MJ of energy to an x-ray source. They will use this source to irradiate a volume of neutral gas, likely of N, on a scale of a few mm to a few cm, increasing with source energy. For a gas pressure of several to ten atmospheres at room temperature, and a source temperature near 100 eV, one will be able to drive a photoionization front through a system of tens to hundreds of photon mean free paths. The front should make the familiar transition from the so-called R-Type to D-Type as the radiation flux diminishes with distance. The N is likely to reach the He-like state. Preheating from the energetic photons appears unlikely to become large enough to alter the essential dynamics of the front beyond some layer near the surface. For well-chosen experimental conditions, competing energy transport mechanisms are small.
Authors:
ORCiD logo [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [3] ;  [3] ; ORCiD logo [4]
  1. Univ. of Michigan, Ann Arbor, MI (United States)
  2. Nuclear Research Center-Negev (Israel)
  3. Univ. of Rochester, Rochester, NY (United States)
  4. ARTEP Inc., Ellicot City, MD (United States)
Publication Date:
Grant/Contract Number:
NA0002719
Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 833; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Research Org:
Univ. of Michigan, Ann Arbor, MI (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA), Office of Defense Programs (DP) (NA-10)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; atomic processes; dark ages; reionization; first stars; galaxies: structure
OSTI Identifier:
1338257

Drake, R. P., Hazak, G., Keiter, P. A., Davis, J. S., Patterson, C. R., Frank, A., Blackman, E. G., and Busquet, Michel. Design of laboratory experiments to study photoionization fronts driven by thermal sources. United States: N. p., Web. doi:10.3847/1538-4357/833/2/249.
Drake, R. P., Hazak, G., Keiter, P. A., Davis, J. S., Patterson, C. R., Frank, A., Blackman, E. G., & Busquet, Michel. Design of laboratory experiments to study photoionization fronts driven by thermal sources. United States. doi:10.3847/1538-4357/833/2/249.
Drake, R. P., Hazak, G., Keiter, P. A., Davis, J. S., Patterson, C. R., Frank, A., Blackman, E. G., and Busquet, Michel. 2016. "Design of laboratory experiments to study photoionization fronts driven by thermal sources". United States. doi:10.3847/1538-4357/833/2/249. https://www.osti.gov/servlets/purl/1338257.
@article{osti_1338257,
title = {Design of laboratory experiments to study photoionization fronts driven by thermal sources},
author = {Drake, R. P. and Hazak, G. and Keiter, P. A. and Davis, J. S. and Patterson, C. R. and Frank, A. and Blackman, E. G. and Busquet, Michel},
abstractNote = {This study analyzes the requirements of a photoionization-front experiment that could be driven in the laboratory, using thermal sources to produce the necessary flux of ionizing photons. It reports several associated conclusions. Such experiments will need to employ the largest available facilities, capable of delivering many kJ to MJ of energy to an x-ray source. They will use this source to irradiate a volume of neutral gas, likely of N, on a scale of a few mm to a few cm, increasing with source energy. For a gas pressure of several to ten atmospheres at room temperature, and a source temperature near 100 eV, one will be able to drive a photoionization front through a system of tens to hundreds of photon mean free paths. The front should make the familiar transition from the so-called R-Type to D-Type as the radiation flux diminishes with distance. The N is likely to reach the He-like state. Preheating from the energetic photons appears unlikely to become large enough to alter the essential dynamics of the front beyond some layer near the surface. For well-chosen experimental conditions, competing energy transport mechanisms are small.},
doi = {10.3847/1538-4357/833/2/249},
journal = {The Astrophysical Journal (Online)},
number = 2,
volume = 833,
place = {United States},
year = {2016},
month = {12}
}