# MAGNETIC FIELDS FROM QCD PHASE TRANSITIONS

## Abstract

We study the evolution of QCD phase transition-generated magnetic fields (MFs) in freely decaying MHD turbulence of the expanding universe. We consider an MF generation model that starts from basic non-perturbative QCD theory and predicts stochastic MFs with an amplitude of the order of 0.02 {mu}G and small magnetic helicity. We employ direct numerical simulations to model the MHD turbulence decay and identify two different regimes: a 'weakly helical' turbulence regime, when magnetic helicity increases during decay, and 'fully helical' turbulence, when maximal magnetic helicity is reached and an inverse cascade develops. The results of our analysis show that in the most optimistic scenario the magnetic correlation length in the comoving frame can reach 10 kpc with the amplitude of the effective MF being 0.007 nG. We demonstrate that the considered model of magnetogenesis can provide the seed MF for galaxies and clusters.

- Authors:

- Faculty of Exact and Natural Sciences, Javakhishvili Tbilisi State University, 1 Chavchavadze Avenue, Tbilisi 0128 (Georgia)
- McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States)
- Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-10691 Stockholm (Sweden)

- Publication Date:

- OSTI Identifier:
- 22086468

- Resource Type:
- Journal Article

- Journal Name:
- Astrophysical Journal

- Additional Journal Information:
- Journal Volume: 759; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; AMPLITUDES; ASTROPHYSICS; COMPUTERIZED SIMULATION; CORRELATIONS; DECAY; GALAXIES; HELICITY; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; PHASE TRANSFORMATIONS; QUANTUM CHROMODYNAMICS; STAR CLUSTERS; STOCHASTIC PROCESSES; TURBULENCE; UNIVERSE

### Citation Formats

```
Tevzadze, Alexander G., Kisslinger, Leonard, Kahniashvili, Tina, and Brandenburg, Axel, E-mail: aleko@tevza.org.
```*MAGNETIC FIELDS FROM QCD PHASE TRANSITIONS*. United States: N. p., 2012.
Web. doi:10.1088/0004-637X/759/1/54.

```
Tevzadze, Alexander G., Kisslinger, Leonard, Kahniashvili, Tina, & Brandenburg, Axel, E-mail: aleko@tevza.org.
```*MAGNETIC FIELDS FROM QCD PHASE TRANSITIONS*. United States. doi:10.1088/0004-637X/759/1/54.

```
Tevzadze, Alexander G., Kisslinger, Leonard, Kahniashvili, Tina, and Brandenburg, Axel, E-mail: aleko@tevza.org. Thu .
"MAGNETIC FIELDS FROM QCD PHASE TRANSITIONS". United States. doi:10.1088/0004-637X/759/1/54.
```

```
@article{osti_22086468,
```

title = {MAGNETIC FIELDS FROM QCD PHASE TRANSITIONS},

author = {Tevzadze, Alexander G. and Kisslinger, Leonard and Kahniashvili, Tina and Brandenburg, Axel, E-mail: aleko@tevza.org},

abstractNote = {We study the evolution of QCD phase transition-generated magnetic fields (MFs) in freely decaying MHD turbulence of the expanding universe. We consider an MF generation model that starts from basic non-perturbative QCD theory and predicts stochastic MFs with an amplitude of the order of 0.02 {mu}G and small magnetic helicity. We employ direct numerical simulations to model the MHD turbulence decay and identify two different regimes: a 'weakly helical' turbulence regime, when magnetic helicity increases during decay, and 'fully helical' turbulence, when maximal magnetic helicity is reached and an inverse cascade develops. The results of our analysis show that in the most optimistic scenario the magnetic correlation length in the comoving frame can reach 10 kpc with the amplitude of the effective MF being 0.007 nG. We demonstrate that the considered model of magnetogenesis can provide the seed MF for galaxies and clusters.},

doi = {10.1088/0004-637X/759/1/54},

journal = {Astrophysical Journal},

issn = {0004-637X},

number = 1,

volume = 759,

place = {United States},

year = {2012},

month = {11}

}