oops, not simple and certainly not for an Arduino (please prove me wrong;)
- some backgrounders ?
Otherway, if you know a website that does provide the measurements of the SOHO satelite you could just do some web scraping (just the part you're interested in and let those numbers be processed by Arduino, e.g. increase the frequency of the blinking LED when a CME passes by
CME = Coronal Mass Ejection (that are the real bad things for us humans)
check - http://spaceweather.com/
- for some data to parse ..