Observations and Extended MHD Modeling of Magnetized Plasma Bubbles Launched into a Magnetized Background Plasma

The interaction of magnetized flowing plasmas with background plasma is a topic of wide interest in astrophysics as well as high temperature laboratory plasmas.  In this work, hot, dense, plasma structures are launched from a coaxial plasma gun into a background low density magnetized lab plasma.  The dense gun plasma drags frozen-in magnetic flux into the chamber’s background magnetized plasma, providing a rich set of dynamics to study magnetic relaxation, boundary instabilities, magnetic and density turbulence, and magnetized shocks.  Magnetic and electrostatic probe measurements and visible spectroscopy measurements, as well as fast multi-frame imaging will be presented in comparison with preliminary modeling using the Perseus extended MHD (XMHD) code.  Recent experiments show a possible magnetic Rayleigh-Taylor (MRT) instability that appears asymmetrically at the interface between launched spheromaks (bubbles) and their entraining background magnetic field and plasma.  Efforts to understand this instability using in situ measurements, new chamber boundary conditions, and ultra-fast camera and probe data will be presented.