Final Report Summary - COSMOLAB (Laboratory simulation of cosmological magnetic fields)
Magnetic fields exist throughout galactic and intergalactic space, what is puzzling is how they were originally created and how they became so strong. An high-power laser is used to explode a rod of carbon, similar to a pencil lead, into an ambient gas. The explosion drives a powerful shock wave to mimic processes that occur during the formation of galaxies. The experiment shows that within a microsecond of the explosion magnetic fields formed around a shock wave. By scaling the experimental results to the astrophysical system, we have found that the measured magnetic field matched the tiny magnetic seeds predicted by theoretical studies of galaxy formation.
While both our laboratory measurements and previous numerical simulations agree on the magnetic field estimates, their values are several orders of magnitude smaller than present-day observations from synchrotron emission or Faraday rotation. One possible explanation is that other mechanisms such as turbulence or plasma instabilities could further enhance the generation of magnetic field. We have thus started to investigate the effect of shock propagation into a clumpy medium - to mimic, for example, a supernova remnant shock sweeping an inhomogeneous interstellar medium. Our laboratory experiments shows that tangling of the field lines in a turbulent plasma amplifies the magnetic energy.
This work opens up the exciting prospect that we will be able to explore the physics of the cosmos, stretching back billions of years, in a laser laboratory here on Earth.
While both our laboratory measurements and previous numerical simulations agree on the magnetic field estimates, their values are several orders of magnitude smaller than present-day observations from synchrotron emission or Faraday rotation. One possible explanation is that other mechanisms such as turbulence or plasma instabilities could further enhance the generation of magnetic field. We have thus started to investigate the effect of shock propagation into a clumpy medium - to mimic, for example, a supernova remnant shock sweeping an inhomogeneous interstellar medium. Our laboratory experiments shows that tangling of the field lines in a turbulent plasma amplifies the magnetic energy.
This work opens up the exciting prospect that we will be able to explore the physics of the cosmos, stretching back billions of years, in a laser laboratory here on Earth.