# Estimate of a non-helical electroweak primordial bootstrap field today

## TL;DR

This paper estimates the current strength of a primordial non-helical magnetic field originating from the electroweak phase transition, finding it consistent with observational lower limits and providing a comparison with helical field scenarios.

## Contribution

The study provides a novel estimate of the present-day magnitude of a non-helical primordial magnetic field from the electroweak epoch, including its correlation scale and comparison with helical cases.

## Key findings

- Primordial field strength today is about 10^{-14} G at 2 kpc scale.
- Initial field at electroweak transition was 10^{23}-10^{24} G.
- Results align with observational lower limits on intergalactic magnetic fields.

## Abstract

We estimate the magnitude today of the primordial magnetic field originating at the electroweak phase transition. We find that the field, which at the electroweak phase transition is originally of order $10^{23}-10^{24}$ G correlated over the Hubble scale, today is of order $10^{-14}$ G at a scale of order 2 kpc. This result is consistent with the lower limit on the strength of intergalactic magnetic fields obtained by Neronov and Vovk from observations of TeV blazars. The field is non-helical. We compare our results with the helical case discussed by Field and Carroll.