Explaining how magnetic fields formed around galaxies is not an easy task. Similarly, figuring out how these fields emerged in the first place is still a mystery. Now, experts are using a laser capable of simulating conditions occurring during supernova explosions to mimic the early Universe.
In a series of new experiments carried out in the lab, investigators at the University of Oxford, led by physicist Gianluca Gregori, were able to demonstrate that the “Biermann battery effect” may be responsible for generating the mysterious magnetic fields.
One of the things that researchers know for certain about visible matter in the Universe is that its most basic component is hydrogen gas. The gas is made up of electrons with a negative charge, which spin around positively-charged protons at great speed.
The Biermann battery effect hypothesizes that electrons are a lot easier to push around than protons, on account of their smaller mass. Another implication is that external influences can drive an exodus of electrons, without influencing the protons.
As this happens, a small magnetic field is created where the disturbed electrons start to spin. Astrophysicists had proposed that the magnetic fields around galaxies were modeled on smaller seeds, but they were unable to actually demonstrate that until now.
The small magnetic eddies that develop inside hydrogen gas can then be amplified by a large number of other cosmic processes. Eventually, a very large and powerful magnetic field is produced.
In the new studies, experts used a 500-micron carbon rod as a target for a strong laser source. The amount of energy collisions between the two emitted was roughly equivalent to the amount of energy Earth receives from the Sun in a full year.
In effect, the team recreated the conditions that occur during a supernova event. Gregori, an Oxford physicist and the lead author of the new study, explains that the collisions force the carbon rod to bend, producing shock waves that travel through the space around it.
Since the rod is inserted into low-pressure helium gas, the shock waves give rise to disturbances that were proven capable of generating magnetic fields. “We were able to reproduce, albeit in a scaled manner, plasma conditions found in the early universe directly in a laboratory setting,” Gregori says.
Details of the study were published in the January 26 issue of the top scientific journal Nature, Space