Modelling Rapid Target Heating through the Discontinuous Galerkin and Material Point Methods

We present results from our efforts to model the plume generated by the rapid heating of an aluminum target via a time-dependent heat source that emulates an electron beam.

The plasma plumes generated by such extreme heating processes can impact experiments, making an accurate prediction of their behavior important for both design and analysis. Experiments were performed using rapid pulses of about 10¹⁵ electrons to heat targets to temperatures in excess of 1 eV, with shadowgraph and interferometer measurements providing snapshots of the plume’s temperature and electron density.

We approximate this high mach number experiment in two ways. The first is using the Discontinuous Galerkin method to simulate ideal-gas hydrodynamics to model plume evolution, specifically using a slope limiter and positivity preserver to model the shocks in the simulations. Next is using the material point method with a linear elastic and ideal gas model coupled via a phase change. Initial simulations show promise in DG’s capability to model the rapid expansion of the plume, while MPM simulations are able to handle the solid mechanics of the target well.

Research presented is supported by the Laboratory Directed Research and Development program of Los Alamos National Laboratory.