Generation of Strong Fields to Study the Phase Transitions of Magnetized Warm Dense Matter

Warm dense matter is a regime where Fermi degenerate electrons play an important role in the macroscopic properties of a material. While recent experiments have helped us better understand the unmagnetized processes in such dense materials,[i]^{–[ii][iii][iv][v]} their magnetized counterpart has been more difficult to study. Although there are examples of dynamic field compression that generate extremely large magnetic fields by compressing a premagnetized cylindrical target,[vi]^{–[vii][viii][ix]} this approach uses multiple high-power laser beams to ablate the outer surface of the target. The plasma compressing the field is so dense that the fast-heating laser beam required to produce warm dense matter cannot penetrate where the field is the strongest. Numerical simulations are used to show that magnetic-field compression is also possible by shining the laser beams onto the inner, rather than outer, surface of the target. This approach relies on field compression by a low-density, high-temperature plasma, rather than a high-density, low-temperature plasma used in the more conventional approach. The region of the large magnetic field, now mostly free of plasma, allows the compression beam to reach the sample of warm dense matter in the region where the magnetic field is the strongest.

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