A new solar storm prediction system based in Antarctica could provide astronauts in space warning time of over two hours for them to take cover after massive flares or Coronal Mass Ejections erupt from the Sun. The South Pole Neutron Monitor is able to forecast the radiation intensity of solar protons using two different types of neutron detectors installed at the geographic South Pole, which measures gigaelectron volt neutrons that are produced during a solar storm.
The designers of the device have been testing it and say it could provide a warning times of up to 166 minutes, depending on the protons’ energy. Additionally, the team says, it is a practical system for forecasting peak intensity of solar energetic protons in the tens to hundreds of megaelectron volt energy range.
With activity on the Sun increasing as the Solar Maxiumum approaches, there will likely be heightened rates of flares and CMEs, putting at risk the human presence in space, which will likely be ever-increasing, with the advent of commercial space flights and NASA’s plans to send astronauts into deep space, along with crews of six that are usually on board the International Space Station. Even people in airplanes at high altitudes near the poles can be exposed to this increased radiation. Exposure can potentially cause radiation sickness, with symptoms such as fever and vomiting.
During a solar flare or CME, particles from the Sun can be accelerated to very high energies—in some cases traveling near the speed of light. Protons with energies surpassing 100 megaelectron volts essentially sandblast everything in their path.
S.Y. Oh from Chungnam National University in South Korea and an international team of researchers have created and installed the warning system at the Amundsen-Scott South Pole Station. Using one detector located indoors and another outside, they can measure the intensity of the much faster gigaelectron volt neutrons also produced during a solar storm when protons interact with Earth’s atmosphere. By combining the observations of the two detectors, they can then extrapolate this spectrum to estimate the peak intensity and event-averaged flux (fluence) of the later-arriving megaelectron volt protons.
The team compared their predictions for 12 solar events against observations made by geosynchronous satellites, such as some of the GOES satellites, and found their measurements were similar for intensity and fluence predictions for protons with energies higher than 40 and 80 megaelectron volts, respectively.
The researchers say the system could be useful for forecasting radiation hazard, because peak intensity and fluence are closely related to the known medical thresholds of radiation doses.
The lead times would allow for astronauts to take shelter in a shielded area of their spacecraft, or polar-flying airplanes ample time to reduce their altitude to be protected by Earth’s magnetic field.
Read the team’s paper: South Pole neutron monitor forecasting of solar proton radiation intensity
Lead image caption: The South Pole neutron monitor. Credit: University of Delaware.