A SEP event is underway. We have become magnetically conected to Sunspot Region 1429. At the time of this original post the 10MeV Integral Flux has exceeded 100pfu.
NOAA Scale: S2 - Moderate
Potential Impacts: Radiation - Passengers and crew in high latitude, high altitude flights may experience small, increased radiation exposures.
Spacecraft - Infrequent single-event upsets to satellites are possible.
Radio - Small effects on polar HF (high frequency) propagation resulting in fades at lower frequencies.. Additional flaring from region 1429 will rapidly increase this proton flux. When our "foot point" location, the area that we are magnetically conected to the Sun at becomes located at or very near an active region the connection allows Solar Energetic Particles such as protons and electrons to travel an extremely fast and direct path to Earth during a Solar Flare from that region. These Solar Energetic Particles travel at approximately 80% the speed of light and start bombarding the Ionosphere, within a few hours of a Solar Flare. Additionally, during these events, CME driven shocks contribute to accelerating these particles. This Event was precipitated by the X 5.4 flare released early March 7, 2012 at 00:40 UT from Sunspot Region 1429.
Here we can see the proximity of Earths "Foot Point" location to Sunspot Region 1429 just prior to the X 5.4 Solar Flare. Given this interplanetary magnetic field (IMF) connection between Sunspot Region 1429 and the Earth, very energetic solar protons have began saturating the Ionosphere. A more delayed effect may result with the CME that was produced with this X flare. Since the radial propagation speed is expecded to be < 1000km/s with the arrival of the associated CME expected tomorrow March 8, the high solar wind speed accompanying the shock , plus high plasma number densities with a strong southward IMF, we can expect a sudden storm commencement or (SSC). These geomagnetic storms generally produce large magnetic disturbances due to ring current enhancements.
Space Weather Message Code: ALTPX3
Serial Number: 25
Issue Time: 2012 Mar 07 1417 UTC
ALERT: Proton Event 10MeV Integral Flux exceeded 1000pfu
Begin Time: 2012 Mar 07 1410 UTC
NOAA Scale: S3 - Strong
Potential Impacts: Radiation - Passengers and crew in high latitude, high altitude flights may experience increasing radiation exposures. Astronauts on EVA (extra-vehicular activity) are exposed to elevated radiation levels.
Spacecraft - Single-event upsets to satellite operations, noise in imaging systems, and slight reduction of efficiency in solar panels are likely.
Radio - Degraded or episodically blacked-out polar HF (high frequency) radio propagation.
Update - March 9, 2012 @ 17:40 UTC
SEP event continues into March 9, 2012. We are now into the 2nd full day of protons remaining above the event level. A S2 Solar Radiation Strom is in effect at this time
Solar Radiation Storm Levels
Issue Time: 2012 Mar 09 1740 UTC
EXTENDED WARNING: Proton 100MeV Integral Flux above 1pfu expectedExtension to Serial Number: 57
Valid From: 2012 Mar 07 0300 UTC
Now Valid Until: 2012 Mar 10 1200 UTC
Warning Condition: Persistence
Potential Impacts: An enhancement in the energetic portion of the solar radiation spectrum may indicate increased biological risk to astronauts or passengers and crew in high latitude, high altitude flights. Additionally, energetic particles may represent an increased risk to all satellite systems susceptible to single event effects. This information should be used in conjunction with the current Solar Radiation Storm conditions when assessing overall impact
We can now see these particles interfering with SOHOs Lasco C2 camera. This "Snow" is caused by energetic particles getting into the camera's CCD.
Radio communications using high frequency 3 - 30 MHz depend on reflection of the signals in the ionosphere. Radio waves are typically reflected near the peak of the F2 layer approx 300 km in altitude. As radio waves travel along to the F-2 layer and back they suffer "attenuation" or weaken due to absorption by the ionosphere.
Absorption is the process by which the energy of radio waves is converted into heat and electromagnetic noise through interactions between the radio wave, ionospheric electrons, and the atmosphere. Most of the absorption occurs in the Ionospheric D Region, 50–90 km in altitude. The precipitation of protons and other ions into the earth’s atmosphere during a Solar Energetic Particle (SEP) event can also create significant enhancements of ionospheric electron densities in the D region. Solar protons with energies between 1 to 200 MeV are primarily responsible for most of ionization of the D region and, consequently, for the ionospheric absorption of high frequency radio waves. Because of shielding of the Earth by its magnetic field SEPs must travel down the magnetic field lines to the polar regions in order to gain acccess to latitude regions around the Earth’s geomagnetic poles. Such occurrences are therefore termed Polar Cap Absorption (PCA) events. The red shaded areas in the above image over the polar caps indicate the intensity of PCA event occuring today. The current recovery time for high lattitude protons is 47 Hrs and 27 min.
Images courtesy of ISWA, NASA, NOAA