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Published on: December 1, 2020
A platform for planar dynamic compression of crystalline hydrogen toward the terapascal regime
A K Schwemmlein1,2, G W Collins1,2, A J LaPierre2,3
1Department of Mechanical Engineering, University of Rochester, Rochester, New York 14620, USA.
Abstract:
We describe a method for laser-driven planar compression of crystalline hydrogen that starts with a sample of solid para-hydrogen (even-valued rotational quantum number j) having an entropy of 0.06 kB/molecule at 10 K and 2 atm, with Boltzmann constant kB. Starting with this low-entropy state, the sample is compressed using a small initial shock (<0.2 GPa), followed by a pressure ramp that approaches isentropic loading as the sample is taken to hundreds of GPa. Planar loading allows for quantitative compression measurements; the objective of our low-entropy compression is to keep the sample cold enough to characterize crystalline hydrogen toward the terapascal range.
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