Probing Planetary Interior States with Multi-Shock Compression of Hydrogen in Diamond Anvil Cells

Hydrogen is the primary component of gas giant planets, and its behavior profoundly influences their structure and long-term evolution [1]. In particular, hydrogen metallization and resultant immiscibility with helium and neon may account for the observed depletion of the latter in Jupiter’s atmosphere [2, 3]. We combined static precompression and multi-shock dynamic compression to probe the insulator-conductor transition of warm dense hydrogen at the conditions of gas giant interiors using velocity interferometry and optical pyrometry. We observed the onset of absorption at shock pressures near 20 GPa and temperatures near 1,500 K followed by a reflective, metallic-like state at the reshock. These observations inform our understanding of the hydrogen phase diagram and its influence on planetary interior processes.

[1] Guillot et al., Treatise on Geophysics, 2015

[2] Niemann et al., Science 1996

[3] Wilson and Militzer, Phys. Rev. Lett., 2010