The Generation of Warm Dense Matter Using a Magnetic Anvil Cell

Warm dense matter is present at the heart of gas giants and large exo-planets. Yet, its most basic properties are unknown, limiting our understanding of planetary formation and evolution. In this state, where pressure climbs above 1 Mbar, matter is strongly coupled and quantum degenerate. This combination invalidates most theories capable of predicting the equation of state, the viscosity, or heat conductivity of the material. When such properties are missing, understanding planetary evolution becomes an arduous endeavor. Henceforth, research in this field is actively growing, using high-power laser or heavy ion beams to produce samples dense enough to overcome the 1-Mbar limit. These samples are not actively confined and tend to expand rapidly, precluding the existence of any thermodynamically stable equilibrium. However, a mega-ampere-class pulsed-power generator can produce confined matter in the Mbar range, providing two conditions are being met. First, the sample needs to be compressed cylindrically, to maximize magnetic pressure (compared to slab compression). Second, an “electrical damper” must be used to limit the formation of a plasma at the sample surface. This corona robs the main sample from valuable current and limits the homogeneity of the compression. According to numerical simulations, the setup proposed here, called a magnetic anvil cell (MAC), can reach pressures on the order of 1 Mbar using a mega-ampere pulsed-power driver. These samples span several millimeters in length. Unlike diamond anvil cell, the MAC has virtually no pressure limit. Furthermore, the current heats the sample to several eV, a temperature well beyond the capabilities of diamond anvil cells.