Strong (S3) solar radiation storm in progress (May 23, 2013)


Solar radiation storm reached S3 (Strong) levels at approximately 03:00 UTC on May 23, 2013. Strong solar radiation storm is still in progress due an M5.0 solar flare originating in departing Sunspot 1745 on the Sun's western limb. The M-class flare peaked at 13:32 UTC on May 22, 2013 and produced a partial-halo coronal mass ejection (CME). We can expect a hit our geomagnetic field on May 24/25, 2013. High-latitude sky watchers should be alert for auroras.

Solar flare and protons hitting LASCO C2 coronograph onboard SDO's spacecraft (Credit: SDO/ The Watchers)

A high-energy solar protons are hitting the CCD cameras in SOHO's LASCO C2 coronagraph (image above).

SDO/AIA 304, GOES X-Ray flux and ACE HE protons (Credit: SDO/ACE/SWPC)

Solar radiation storm is elevated level of radiation that occur when the numbers of energetic particles increase. NOAA/SWPC issued S3 (Strong) Solar Radiation Storm level. At S3 conditions passengers and crew in high-flying aircraft at high latitudes may be exposed to radiation risk (pregnant women are particularly susceptible) and astronauts on EVA are advice to take radiation hazard avoidance measures. Satellite operations, single-event upsets, noise in imaging systems, and slight reduction of efficiency in solar panel are likely. Degraded HF radio propagation through the polar regions and navigation position errors are also likely.

Protons greater than 100 MeV at geosynchronous orbit reached a peak level of 3 pfu at 18:30 UTC. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 722 pfu. Protons are expected to continue to rise  and are likely to cross threshold on May 25, 2013.

Limited blackout of HF radio communication on sunlit side, loss of radio contact for tens of minutes, degradation of low-frequency navigation signals for tens of minutes are possible so NOAA/SWPC issued R2 (Moderate) Radio Blackout.


Solar wind
speed: 267.7 km/sec
density: 0.5 protons/cm3

Planetary K-index
Now: Kp= 3 quiet
24-hr max: Kp= 3 

Interplanetary Mag. Field
Btotal6.1 nT
Bz2.4 nT south

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