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

[摘要] 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 CF2target 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 Teand density Neprofiles of the plasma are obtained. It is shown that Nedecreases monotonically in the case without B-field, but demonstrates an extended density profile up to 10 mm when 20 T magnetic field is applied. Nevalues are consistent with that observed via interferometry diagnostics, thus providing the confidence in our x-ray spectroscopy analysis techniques.

[发布机构] Joint Institute for High Temperatures, Russian Academy of Sciences, Izhorskaya 13 Bldg 2, Moscow; 125412, Russia^1;Lawrence Livermore National Laboratory, East Ave 7000, Livermore; CA; 94550, United States^2;GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstrafie 1, Darmstadt; 64291, Germany^3;Laboratoire Pour l'Utilisation des Lasers Intenses, CNRS-CEA, École Polytechnique, Physique Atomique dans les Plasmas Denses, Route de Saclay, Palaiseau; F-91128, France^4

[关键词] External magnetic field;Large aspect ratio;Laser generated plasmas;Poloidal magnetic field;Relative intensity;Spatial resolution;Spatially resolved;X-ray emission spectra