Parameters of supersonic astrophysically-relevant plasma jets collimating via poloidal magnetic field measured by x-ray spectroscopy method

Application of external magnetic field to a laser-generated plasma flows allows to investigate stable, large aspect ratio plasma jets which are relevant to a number of astrophysical cases. In the experiment with 0.6 ns, 40 J laser pulses focused to 700 μm focal spot at solid CF₂ target in presence of 20 T poloidal magnetic field the parameters of the plasma jet were studied by means of spatially resolved x-ray spectroscopy. Focusing spectrometer with spatial resolution was used to record the temporally-integrated x-ray emission spectra of the plasma with spatial resolution along the jet propagation. Using the relative intensities of spectral lines emitted by F He-like ions, the electron temperature T_e and density N_e profiles of the plasma are obtained. It is shown that N_e decreases monotonically in the case without B-field, but demonstrates an extended density profile up to 10 mm when 20 T magnetic field is applied. N_e values are consistent with that observed via interferometry diagnostics, thus providing the confidence in our x-ray spectroscopy analysis techniques.