How quickly can the highly hazardous Solar Energetic Particles (SEPs) reach Earth following a related solar flare?

Answer

As little as 15 to 30 minutes

SEPs travel much faster than associated CME plasma, meaning a major radiation storm can reach Earth in as little as 15 to 30 minutes following the initial flare.

How quickly can the highly hazardous Solar Energetic Particles (SEPs) reach Earth following a related solar flare?
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