Do you have any idea how quickly the corona ejection would travel, and hence how long it would take to hit earth? It would take a bit over 8 minutes for any mes

Do you have any idea how quickly the corona ejection would travel, and hence how long it would take to hit earth? It would take a bit over 8 minutes for any message from a probe near the sun to reach us, and if the ejection is travelling at (random number) 0.5c, it would only give us a bit over 8 minutes to react and get the word out. Obviously, if it was slower (0.1c), we would have a lot more time. The worst case scenario would be it travelling at >0.9c, giving us under two minutes to react and do everything. It's perhaps a much, much better solution to keep a large (and I mean really fucking large, since it might be all we had to bootstrap ourselves back up to our current level of technology) store of equipment in a large Faraday cage. Probably several, distributed for redundancy, really. This could be combined with probes, of course.