This chart shows the proton flux, or density, in the charged particle stream coming from the Sun, as measured by the GOES spacecraft and reported by ESA's SEISOP space weather assessment tool. The vertical scale shows particle density at three different energies, 0.8-4 MeV (megaelectron volts) in red, 15-40 MeV in blue and 40-80 MeV in green. The horizontal scale shows time between 4 and 13 December 2006.