X-Ray Spectral Diagnostics of Superstrong Magnetic Fields in Ultrarelativistic Laser Plasma

Under the action of ultrarelativistic laser radiation on microstructured targets, matter in an extreme state can be formed i.e., with a close to solid-state density and superstrong magnetic fields. Experimental diagnostics of such fields by optical methods turns out to be impossible due to the high density and self-radiation of the plasma; therefore, X-ray spectral methods become more relevant. The paper discussed the key features of this diagnostic technique for superstrong magnetic fields, based on the analysis of the shape of the profiles of spectral lines emitted by multiply charged plasma ions. As an example, we consider targets with a structure formed by regular rods of micron-size matter irradiated by laser pulses with parameters corresponding to pulses of the advanced XCELS facility under construction.