Although bipolar jets are seen emerging from a wide variety of astrophysical systems, the issue of their formation and morphology beyond their launching is still under study. Our scaled laboratory experiments, representative of young stellar object outflows, reveal that stable and narrow collimation of the entire flow can result from the presence of a poloidal magnetic field whose strength is consistent with observations. The laboratory plasma becomes focused with an interior cavity. This gives rise to a standing conical shock from which the jet emerges. Following simulations of the process at the full astrophysical scale, we conclude that it can also explain recently discovered x-ray emission features observed in low-density regions at the base of protostellar jets, such as the well-studied jet HH 154.
Recently, EU researchers have tried to explain the formation of jets emitted by young stars. In good agreement with astrophysical observations, the model, which involves the interstellar magnetic field, was developed by an international collaboration led by French teams at
- Laboratoire pour l'Utilisation des Lasers Intenses (LULI, CNRS/École Polytechnique/UPMC/CEA)
- Laboratoire d'Etudes du Rayonnement et de la Matière en Astrophysique et atmosphères (LERMA, Observatoire de Paris/CNRS/UPMC/Université de Cergy-Pontoise/ENS Paris)
- Laboratoire National des Champs Magnétiques Intenses (LNCMI, CNRS).
A typical simulation result of formation of young star stellar jets, showing density and magnetic fields. The magnetic field lines are shown in white.
Scientific results have been published in the high-profile journal Science.