Developing sustainable clean energy sources, studying the degenerate states of matter or understanding the dynamics of the Universe require a detailed knowledge of the basic mechanisms ruling extremely high pressure ionized gases, also called high energy density (HED) plasmas. In particular, the advection of the magnetic field by HED plasmas remains an open question to the international scientific community. This research program investigates this topic using radial foil configurations. In this experimental arrangement, a thin metallic foil is driven by a large pulsed power generator. A pin cathode contacts the foil at its geometrical center while the foil periphery is connected to a circular anode. The converging electrical currents produce a plasma pressure close to a mega-bar, a million times the earth atmospheric pressure. The experimental setup benefits from quasi symmetric plasma dynamics and excellent diagnostic access. This configuration permits a three dimensional reconstruction of plasma properties such as magnetic field, mass density, velocity and temperature. By combining multiple measurements spaced in time, this research analyzes the time evolution of the plasma parameters and highlights the mechanisms ruling magnetic field advection in HED plasmas.
This research program also impacts other area of plasma physics. We plan to compare experimental results to numerical computations to validate advanced plasma models. As plasma theory and numerical modeling can be used by the larger plasma physics community, this research will benefit other areas of plasma research, such as magnetic confinement fusion. Furthermore, the research investigates the interaction of the magnetic field with supersonic plasma flows, which are ubiquitous astrophysical occurrences encountered in supernovae and accretion disks surrounding black holes. Due to favorable scaling laws, plasmas generated by radial foils can help to unlock astrophysical mechanisms by providing detailed plasma measurements in supersonic regimes. In turn, this data can be used to validate astrophysical theory and numerical codes, fostering cross-pollination between the HED physics and astrophysics communities.
