Solar energetic protons (SEPs), produced in shocks from coronal mass ejections or solar flares, pose a threat to the operations of satellites and a health risk to astronauts as well as passengers and crew on polar airline flights. It is important to characterize this risk in real-time so that, for instance, astronauts can be advised to protect themselves from harmful incoming radiation, aircraft pilots can avoid polar routes, and satellite operators can turn off crucial instruments.
While real-time proton measurements have been available at high altitudes since the 1970s, until now, these measurements have not been available at the much lower altitudes where many satellites, spacecraft, and aircraft operate. The AER SEP Nowcast is the first real-time estimate of proton levels at these operationally- important medium to low Earth altitudes.
The AER SEP Nowcast provides essential warning time for pilots, astronauts, and satellite operators to take immediate action to protect their health and equipment, by estimating the SEP flux in low Earth orbit in real-time. Updated maps are displayed every 10 minutes for a low and medium altitude and a medium and high proton energy.
- Hazardous SEP events have a measured > 10 MeV proton flux of 10 pfu or above. They are indicated by yellow, orange, or red on the map.
- Very low SEP flux values, below 0.01 pfu, are shown in blue.
- During low solar activity, few to none of the hazardous events may occur during the whole year, while highly active times can cause a few events per month.