Rare event 03 21 2011 0957 UTC: Proton flux increased; storm threshold not reached. Back-sided plasma cloud came into view of STEREO B COR2 @ 0254 UTC maybe associated w/proton levels. Earth is magnetically connected w/source site behind Sun. Parker spiral has bended magnetic field lines that guide the electrically charged protons. Earth is near such field lines along which these protons travel. This is a rare event.
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