You can see the real time magnetic field change when it hits: https://dasi.barlow.cpi.com/dashboard
replies(1):
https://intermagnet.org/data_download.html
Example data, (Neumayer Station III in Antarctica)
https://imag-data.bgs.ac.uk/GIN_V1/GINForms2?observatoryIaga...
I wonder why there doesn't seem to be any website with a map view of all of the planet's magnetometers. Looks like there should be more than enough data to make an interesting livemap.
Here's a list of the sites,
https://www.gfz.de/en/section/geomagnetism/infrastructure/ge...