Aircraft passengers are at risk of exposure to galactic and solar-derived cosmic radiation (“galactic cosmic rays” and “solar radiation”).Generally, it is said that the higher the altitude and latitude of an airplane, the higher the exposure dose during flight. In Japan, the public exposure dose limit is 1 mSv per year, while the cosmic radiation exposure dose management target value for aircraft crew members is annual. It is set to 5mSv.
While "galactic cosmic rays" have relatively low dose rates, the intensity of "solar radiation" can suddenly become extremely high when large solar flares occur.Therefore, measures such as cancellation and lowering the flight altitude are required during large solar flares.
This time, researchers at Kyoto University and the National Institute of Maritime, Port and Aviation Technology have conducted the frequency and intensity of solar flares over the past 2000 years, as well as solar radiation exposure, in order to estimate the cost and effectiveness of these measures. The four-dimensional space-time series data of the solar radiation exposure dose rate estimated by the alarm system WASAVIES were combined and analyzed.
As a result, the frequency of solar flares that require measures to avoid exposure such as flight altitude changes to low altitudes and cancellations is estimated to be about once every 17 years, and is calculated from the costs of altitude reduction and cancellations. The annual risk of economic loss is estimated to be up to about US $ 1, even for daily long-haul flights.This value is not so large compared to other aviation risks such as volcanic eruptions, and it has been proved that the threat of exposure to solar flares can be reasonably reduced at a sufficiently low cost.
This study was the first in the world to succeed in quantifying the risk of economic loss associated with changes in aircraft flight plans due to solar radiation exposure, and will be useful in determining optimal aircraft operation countermeasure guidelines and risk countermeasures during future solar flares. It is expected.
Paper information:[Scientific Reports] Probabilistic Risk Assessment of Solar Particle Events Considering the Cost of Countermeasures to Reduce the Aviation Radiation Dose
