The StarAcc project was initiated by Emeric Falize (CEA-DAM) following significant theoretical advances on the existence of scale laws adapted to validly reproduce accretion columns in laboratory and study their processes physics. It is the continuation of the POLAR program for the study of accretion columns in the case of magnetic white dwarfs in binary systems (Polars systems). As part of this program, similarity properties have been shown allowing to achieve the accretion column relevant regimes using existing power lasers (Falize et al., 2011, Falize et al., 2012).
The StarAcc research program is based on three main axes:
- modeling and simulation of astrophysical accretion phenomena,
- experimentation for their reproduction on the scale of the laboratory thanks to the power lasers.
- astrophysical observation for confrontation with astrophysical data
This project brings together at the French level a multidisciplinary group in the three domains of numerical simulation (DAM, SAp, UPMC), high energy density experimentation (DAM, LULI Ecole Polytechnique) and astrophysics (Sap, LUTH).
It is also based on international collaboration in the field of laser experimentation including the CRASH group of R.P. Drake (Michigan University), the groups of R. Kodama and Y. Sakawa (Osaka University), the groups of N. Woolsey (York University) and G. Gregori (Oxford Univ.) and an AWE (UK) team. This collaboration allows access to foreign facilities such as the Omega, GEKKO XII (Japan) and Orion (UK) lasers.
For the astrophysical observation, close collaboration has also been established for several years with the Observatory of South Africa (SAAO), notably providing access to the SALT telescope (10 m in diameter).
The StarAcc project achieved a milestone in 2016 with the POLAR experiment by demonstrating for the first time the possibility of reproducing in the laboratory an accretion structure (accretion shock and radiative zone) in agreement with numerical predictions and astrophysical observations (Cross et al., 2016, Nature Communications 7: 11899).
This result paves the way for the use of high energy lasers, such as the National Ignition Facility (NIF) or the LMJ (Megajoule Laser), to achieve radiative regimes rigorously homothetic to the astrophysical situation.