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Title: Conductivity and dissociation in liquid metallic hydrogen and implications for planetary interiors

Abstract

Liquid metallic hydrogen (LMH) is the most abundant form of condensed matter in our solar planetary structure. The electronic and thermal transport properties of this metallic fluid are of fundamental interest to understanding hydrogen’s mechanism of conduction, atomic or pairing structure, as well as the key input for the magnetic dynamo action and thermal models of gas giants. Here, we report spectrally resolved measurements of the optical reflectance of LMH in the pressure region of 1.4–1.7 Mbar. We analyze the data, as well as previously reported measurements, using the free-electron model. Fitting the energy dependence of the reflectance data yields a dissociation fraction of 65 ± 15%, supporting theoretical models that LMH is an atomic metallic liquid. We determine the optical conductivity of LMH and find metallic hydrogen’s static electrical conductivity to be 11,000–15,000 S/cm, substantially higher than the only earlier reported experimental values. Here, the higher electrical conductivity implies that the Jovian and Saturnian dynamo are likely to operate out to shallower depths than previously assumed, while the inferred thermal conductivity should provide a crucial experimental constraint to heat transport models.

Authors:
 [1];  [1]
  1. Harvard Univ., Cambridge, MA (United States)
Publication Date:
Research Org.:
Harvard Univ., Cambridge, MA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1540263
Grant/Contract Number:  
NA0001990
Resource Type:
Accepted Manuscript
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 114; Journal Issue: 45; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
Science & Technology; Other Topics; liquid metallic hydrogen; phase transitions; planetary interiors

Citation Formats

Zaghoo, Mohamed, and Silvera, Isaac F. Conductivity and dissociation in liquid metallic hydrogen and implications for planetary interiors. United States: N. p., 2017. Web. doi:10.1073/pnas.1707918114.
Zaghoo, Mohamed, & Silvera, Isaac F. Conductivity and dissociation in liquid metallic hydrogen and implications for planetary interiors. United States. doi:10.1073/pnas.1707918114.
Zaghoo, Mohamed, and Silvera, Isaac F. Tue . "Conductivity and dissociation in liquid metallic hydrogen and implications for planetary interiors". United States. doi:10.1073/pnas.1707918114. https://www.osti.gov/servlets/purl/1540263.
@article{osti_1540263,
title = {Conductivity and dissociation in liquid metallic hydrogen and implications for planetary interiors},
author = {Zaghoo, Mohamed and Silvera, Isaac F.},
abstractNote = {Liquid metallic hydrogen (LMH) is the most abundant form of condensed matter in our solar planetary structure. The electronic and thermal transport properties of this metallic fluid are of fundamental interest to understanding hydrogen’s mechanism of conduction, atomic or pairing structure, as well as the key input for the magnetic dynamo action and thermal models of gas giants. Here, we report spectrally resolved measurements of the optical reflectance of LMH in the pressure region of 1.4–1.7 Mbar. We analyze the data, as well as previously reported measurements, using the free-electron model. Fitting the energy dependence of the reflectance data yields a dissociation fraction of 65 ± 15%, supporting theoretical models that LMH is an atomic metallic liquid. We determine the optical conductivity of LMH and find metallic hydrogen’s static electrical conductivity to be 11,000–15,000 S/cm, substantially higher than the only earlier reported experimental values. Here, the higher electrical conductivity implies that the Jovian and Saturnian dynamo are likely to operate out to shallower depths than previously assumed, while the inferred thermal conductivity should provide a crucial experimental constraint to heat transport models.},
doi = {10.1073/pnas.1707918114},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
number = 45,
volume = 114,
place = {United States},
year = {2017},
month = {10}
}

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Cited by: 14 works
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