Solar flares:C-class, M-class and then multiple c-class solar flares

September 21 2011 – M-class solar flare September 21 2011-Solar flare activity all day

The sun erupted into a medium sized C-class solar flare only to be followed by a larger M-class solar flare that existed for an extended period of time.  As this M-class solar flare was slowely fading we saw four C-class solar flares.  Although all of these solar flares are notable we should not have anything more than localized degradation of radio waves if anything at all.

GOES 15 X-Ray Events 1-8A on September 21 2011Solar flares-One M class and four C class solar flares
M-class solar flare
multiple C-class solar flares
Cur 21/1546 C1.9 Ratio 0.026
Beg
21/1204
C1.8
 
Max
21/1223
M1.8
Int 3.4e-02 J m-2
End 21/1245 M1.0

The GOES X-ray flux plot contains 1 minute averages of solar X-rays in the 1-8 Angstrom (0.1-0.8 nm) and 0.5-4.0 Angstrom (0.05-0.4 nm) passbands. Data from the SWPC Primary GOES X-ray satellite is shown.

X-ray alerts are issued at the M5 (5x10E-5 Watts/m2) level, based upon 1-minute data. Large X-ray bursts cause short wave fades for HF propagation paths through the sunlit hemisphere. Some large flares are accompanied by strong solar radio bursts that may interfere with satellite downlinks.