GRB Magnetic Fields (Illustration of Competing Models)

Image Credit: LT Group

Original Caption: Competing models of GRB magnetic field structure for standard fireball model: (a) large-scale ordered magnetic field threaded through the GRB outflow; (b) tangled magnetic field in shock front and line of sight close to jet edge, and (c) shock front contains some independent patches of locally-ordered magnetic fields.

Note:
A (above) was considered the most likely explanation of the magnetic fields in the GRB afterglow: a pervasive large-scale magnetic field present at the time of the GRB / afterglow.

See:
LT Detects 10% Optical Polarisation in Gamma-Ray Burst