4:00 PM - 4:15 PM
[PEM15-19] Geomagnetic Response to Lyman Lines and EUV Emission during Solar Flares
Keywords:solar EUV emission, Earth's Ionospheric E-region, geomagnetic fluctuations, GAIA model
Solar EUV radiation (10-124 nm) is known to have a significant impact on the Earth's ionosphere. Among these, the Lyman-alpha line (Lyα line, 121.6 nm) is the hydrogen line with the strongest irradiance and has the energy to ionize NO molecules present in the D-region (altitude 60-100 km) of the Earth's ionosphere. On the other hand, the Lyman-beta line (Lyβ line, 102.6 nm), which is also a hydrogen Lyman line, has a shorter wavelength than the Lyα line and has the energy to ionize O2 molecules present in the E-region of the ionosphere. Investigating the impact of solar EUV radiation, including these Lyman lines, on the Earth's ionosphere is extremely important from the perspective of space weather.
In this study, we used observational data from SDO/EVE and GOES/EUVS-E to examine the variations in EUV, including Lyman lines, during solar flares. To verify the impact of solar radiation on the Earth's ionosphere, we used the GAIA model (Jin et al., 2011) and magnetometer data from Kakioka and other sources.
As a result, the Lyman lines and He II line showed similar temporal variations, all of which preceded the responses of the magnetometer. This result suggests that these flare line emissions are the cause of the variation in the geomagnetic field. However, the effect of solar flare radiation on the horizontal component of geomagnetic field strength is not always the same and showed various aspects depending on the time and observation location of the flare event. In this study, we discuss the causes of these geomagnetic variations and the effects of solar EUV radiation on the Earth's ionosphere using observational data and model calculations.
In this study, we used observational data from SDO/EVE and GOES/EUVS-E to examine the variations in EUV, including Lyman lines, during solar flares. To verify the impact of solar radiation on the Earth's ionosphere, we used the GAIA model (Jin et al., 2011) and magnetometer data from Kakioka and other sources.
As a result, the Lyman lines and He II line showed similar temporal variations, all of which preceded the responses of the magnetometer. This result suggests that these flare line emissions are the cause of the variation in the geomagnetic field. However, the effect of solar flare radiation on the horizontal component of geomagnetic field strength is not always the same and showed various aspects depending on the time and observation location of the flare event. In this study, we discuss the causes of these geomagnetic variations and the effects of solar EUV radiation on the Earth's ionosphere using observational data and model calculations.