A team led by researchers from the École Polytechnique - Institut Polytechnique de Paris has solved a mystery of astrophysics: Why do many remnants of stellar explosions spread out along an axis rather than in a spherical shape? Previous models predict that the remnants of a supernova should move spherically symmetrically, as the energy is projected in all directions of space during the explosion. However, telescope images show that this expectation is not fulfilled. For example, the supernova remnant G296.5+10.0 is symmetric only along its vertical axis.
The team, which also includes the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), has now investigated this astrophysical phenomenon in the laboratory. They used the pulsed high-power laser of the Intense Lasers Lab (LULI) on the campus of the École Polytechnique. The scientists used a strong magnetic field, around two hundred thousand times stronger than that generated by the Earth, to test various hypotheses. They found that when this field was applied, the shock wave expanded preferentially in only one direction. The results support the idea that a large magnetic field is present around G296.5+10.0 and is responsible for its current shape.
The extreme magnetic fields at the École Polytechnique, which reach a strength of 10 Tesla, originate from a so-called Helmholtz coil, which was jointly developed and built by scientists from the Dresden High-Field Magnetic Laboratory and the Institute of Radiation Physics at the HZDR and which generates almost homogeneous magnetic fields. The coil was fed by a high-voltage pulse generator, which was also developed at the Dresden research center and is now permanently installed at LULI. The astrophysicists now hope to use current and future observations of supernova remnants to determine the strength and direction of magnetic fields throughout the universe.
