The Lorentz term raises the linear matter power on small scale which leads to interesting signatures in the 21 cm signal .
Numerical simulations of the resuting nonlinear density field , the distribution of ionized hydrogen and the 21 cm signal at different values of redshift are presented for magnetic fields with field strength B=5 nG , and spectral indices n _ { B } = -2.9 , -2.2 and -1.5 together with the adiabatic mode for the best fit data of Planck13+WP .
Comparing the averaged global 21 cm signal with the projected SKA1-LOW sensitivities of the Square Kilometre Array ( SKA ) it might be possible to constrain the magnetic field parameters .