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Turbulent Plasma: Uncovering the Source of the Universe’s Magnetic Fields
Science

Turbulent Plasma: Uncovering the Source of the Universe’s Magnetic Fields

Aug 21, 2023
Galactic Magnetic Field Concept Art

Columbia researchers have found that magnetic fields across the universe may originate in turbulent plasma. Their study demonstrates that these plasmas, present in various environments, can spontaneously create and amplify magnetic fields, revealing the process through which magnetic fields can stretch over immense distances.

The source of magnetic fields has long been debated. New research offers clues on their origins.

It isn’t just your refrigerator that has magnets on it. The earth, the stars, galaxies, and the space between galaxies are all magnetized, too. The more places scientists have looked for magnetic fields across the universe, the more they’ve found them. But the question of why that is the case and where those magnetic fields originate from has remained a mystery and a subject of ongoing scientific inquiry.

M51 Whirlpool Galaxy Magnetic Field

The magnetic field in the Whirlpool Galaxy (M51), captured by NASA’s flying Stratospheric Observatory for Infrared Astronomy (SOFIA) observatory superimposed on a Hubble telescope picture of the galaxy. The image shows infrared images of grains of dust in the M51 galaxy. Their magnetic orientation largely follows the spiral shape of the galaxy, but it is also being pulled in the direction of the neighboring galaxy at the right of the frame. Credit: NASA, the SOFIA science team, A. Borlaff; NASA, ESA, S. Beckwith (STScI) and the Hubble Heritage Team (STScI/AURA)

Insights Into Magnetic Field Origins

A new research paper by Columbia scientists offers insight into the source of these fields. The research team used models to show that magnetic fields may spontaneously arise in turbulent plasma.

Plasma is a kind of matter often found in ultra-hot environments like that near the surface of the sun, but plasma is also scattered across the universe in low-density environments, like the expansive space between galaxies; the team’s research focused on those low-density environments.

Their simulations showed that, in addition to generating new magnetic fields, the turbulence of those plasmas can also amplify magnetic fields once they’ve been generated. This helps explain how magnetic fields that originate on small scales can sometimes eventually reach to stretch across vast distances.

Birth and Growth of Magnetic Fields in Turbulent Plasmas

A composite image illustrating the birth and growth of magnetic fields in turbulent plasmas, from weak fields on small scales (top left) to strong fields on large scales (bottom right). Credit: Columbia University

“This new research allows us to imagine the kinds of spaces where magnetic fields are born: even in the most pristine, vast, and remote spaces of our universe, roiling plasma particles in turbulent motion can spontaneously give birth to new magnetic fields,” Sironi said.

“The search for the ‘seed’ that can sow a new magnetic field has been long, and we’re excited to bring new evidence of that original source, as well as data on how a magnetic field, once born, can grow.”

Reference: “Generation of Near-Equipartition Magnetic Fields in Turbulent Collisionless Plasmas” by Lorenzo Sironi, Luca Comisso and Ryan Golant, 31 July 2023, Physical Review Letters.
DOI: 10.1103/PhysRevLett.131.055201

The paper was written by astronomy professor Lorenzo Sironi, astronomy research scientist Luca Comisso, and astronomy doctoral candidate Ryan Golant.


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