The youtube video seemed very hand-wavey, I found the paper that the NASA link refers to on arxiv: https://arxiv.org/abs/1611.03390
I think the relevant part starts at section 8.3, page 48, but it's quite dense so I wasn't able to glean much more from it!
The field seems directional. What will this shield do to radiation coming from larger angles of inclination? Is it unsafer to live near the polar circles?