Core-collapse supernova (CCSN) explosions mark the death of a massive star and are one of the brightest phenomena in the modern universe. These explosions are a cornerstone of astronomy and astrophysics. The energy released plays a critical role in the formation and evolution of galaxies. The explosion itself is responsible for dispersing newly formed elements, including the building blocks of life, throughout the galaxy. CCSNe are also the birth site of neutron stars and black holes.Despite over 50 years of theoretical effort, the exact mechanism and details of how the initial core collapse, an implosion, is converted to an explosion are only now starting to be uncovered. What has become very clear is that the problem is a complex, multiphysics problem that can only be addressed with multidimensional, neutrino-radiation-hydrodynamic simulations.
Over the past several years my colleagues and I have developed an efficient infrastructure for performing simulations of CCSNe with the FLASH hydrodynamics toolkit (Fryxell et al. 2000; Couch 2013; Couch & O'Connor 2014; O'Connor et al. 2017; O'Connor & Couch 2017). We are currently at a position where we can easily perform a large number of 2D (axisymmetry) simulations in order to systematically explore CCSNe. With this medium size allocation on SNIC we will continue our work on systematically studying CCSNe in 2D. During SNIC 2017/1-259, we made significant progress towards our goal but felt that we were not quite ready to make the move to a large allocation. SNIC resources early on in the previous allocation were critical to facilitate the further development of our neutrino-matter interactions in FLASH. A graduate student working with me at Stockholm University (Aurore Betranhandy) has begun working with FLASH and will be extending its capabilities even more. During this previous allocation, SNIC resources were essential for simulations that will be a part of at least 4 publications in 2018. We have begun to study rotating CCSN in 2D, have generated simulations for upcoming comparison papers, and have carried a self-consistent explosion in 2D to more than 2 seconds after the explosion.
With this allocation we will continue these studies of CCSNe in 2D. Our long term simulations tracking the development after the onset of explosion (for seconds) use ~10 000 hours per second of evolution time. We plan to have one or two of these such simulations running at any given time. For determining the success or failure of the explosion multiple seconds on evolution are not needed (typically 0.5 seconds is sufficient), but higher fidelity microphysics is required which costs roughly two times more computational cost, or 10 000 hours per 0.5 second of evolution time. Our request of 50 000 hours on each of Beskow and Kebnekaise will allow us to simulate 1-2 long term evolutions and 8-9 high fidelity simulations each month. This allocation will also serve to prepare our team for submitting a large-size allocation proposal to SNIC in the future.