In almost every application, the use of RAGE has allowed the user to examine new physical situations and systematically discover new phenomena that are generally not accessible by Lagrangian methods. Simply, many of our physical problems have highly unstable hydrodynamic flows and Eulerian codes naturally allow for linear and nonlinear instability growth, whereas Lagrangian codes can usually follow only the linear instability growth phase. Figure 3 is an illustration taken from the results of this article. The benefits of the RAGE revolution, however, do not come without a price. No code is perfect, and no code currently available will solve all classes of problems.
RAGE is no exception.
Our basic philosophy for the development of the RAGE code is to identify the deficiencies of the code and then use this knowledge as a guide for planning code improvements. One of our main tasks, currently, is to improve the fundamental hydrodynamics in the code. With Eulerian hydro it is easy to see the growth of instabilities. The discretization of the materials into mesh cells, in and of itself, introduces perturbations that typically are larger than material surface finishes. In light of these numerical artifacts, we need to assess how much of the calculated instability growth is real and how much is numerically induced.