This award will support Professor Rodolfo Rosales of MIT in a research collaboration with Professor Pablo M. Jacovkis of the University of Buenos Aires, Argentina. The researchers intend to carry out research in the stability theory of square wave detonations. The problem of propagation of reacting shocks in a gaseous combustible media (detonation waves) has interested researchers since the end of the last century. The first models for such propagation were proposed at the beginning of the century but it was soon realized that they were too simple and did not take into account the very rich structure of detonation waves. Since the early 1950's researchers have attempted to understand the theory by investigating the stability of plane detonations. In particular, the Square Wave Model allows for a linearized stability analysis that is relatively simple but leads to contradictory results and "catastrophic instabilities". The researchers intend, through a combination of numerical and analytical studies, to investigate the reasons for such badly believed stability for this model. The project will combine the experience of Prof. Rosales in analytical techniques with the computational background of Prof. Jacovkis.