WADM and radiation MHD simulations of compact multi-planar and cylindricalwire arrays at 1 MA currents

摘要

The radiative performance of Z-pinches created by the imploding wire array loads is defined by the ablationand implosion dynamics of these loads. Both these processes can be effectively modeled by the WireAblation Dynamics Model (WADM), which extends the formalism exploited earlier for the cylindrical wirearrays to the loads of arbitrary geometries. The WADM calculates the ablation rates for each array wire andprovides the important dynamic parameters, such as the specific mass and velocity of the implodingplasma, which can be used to estimate the shapes of the x-ray pre-pulse and, partially, the main x-ray burst.The applications of the WADM also extend to combined material wire array loads. The ablation andimplosion dynamics of novel Prism Planar Wire Array (PPWA) and combined material (Mo/Al/Mo) TriplePlanar Wire Array (TPWA) loads are discussed in detail. The combined WADM and radiation MHD simu-lation is applied to model the radiative performance of the precursor plasma column, created by theimploding stainless steel compact cylindrical wire array. As the radiation effects intensify with the massaccumulation at the array center, the simulation reveals the transformation of quasi-uniform precursorcolumn into a heterogeneous plasma structure with strong density and temperature gradients. We findthat radiative performance of the precursor plasma is greatly affected by the load geometry as well as bythe wire material.