Hydrogen at high pressures and temperatures: implications for Jupiter
Electrical conductivities and shock temperatures were measured for shock-compressed liquid H{sub 2} and D{sub 2}. Conductivities were measured at 93-180 GPa. Calculated densities, temperatures were at 0. 28-0.36 mol/cm{sup 3} and 2000-4000 K. Resistivity data are interpreted in terms of a continuous transition from a semiconducting to metallic, primarily diatomic fluid at 140 GPa and 3000 K. Shock temperatures up to 5200 K were measured up to 83 GPa. Data are interpreted in terms of a continuous dissociative phase transition above 20 GPa. The continuous transition from a molecular to monoatomic fluid means that Jupiter has no distinct core-mantle boundary. The dissociation model derived from the temperature data indicates a dissociation fraction of 5% at 140 GPa and 3000 K. The isentrope of hydrogen was calculated starting from the surface temperature of Jupiter (165 K). At a metallization pressure of 140 GPa in Jupiter, the temperature is about 4000 K and about 10% of the hydrogen molecules are dissociated. The electrical conductivity was calculated along this isentrope by deriving a scaling relation from measured conductivities. Results indicate that hydrogen becomes metallic much closer to the surface of Jupiter than thought previously, a possible explanation of the very large magnetic field of Jupiter, but the metallic conductivity of the molecular fluid is 2 orders of magnitude lower than predicted for the monatomic fluid.
- Research Organization:
- Lawrence Livermore National Lab., CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 461384
- Report Number(s):
- UCRL-JC--125039; CONF-960193--2; ON: DE97051956
- Country of Publication:
- United States
- Language:
- English
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