2021-02-09, 15:00: Dr. Laura Hayes (NASA)
Dr. Laura Hayes
National Aeronautics and Space Administration, USA
Solar flares and their effects of the Earth’s ionosphere
Abstract: Solar flare activity is a powerful factor affecting the geophysical processes of planetary atmospheres. On Earth, the enhancement of EUV and X-ray emission during a flare causes a rapid increase of ionization of the entire dayside ionosphere – the ionized portion of the Earth’s atmosphere. While all layers of the ionosphere are impacted, the effect on the lowest-lying region, the D-region (~60-90 km in altitude), is most apparent. The increased ionization manifests as a substantial increase in the electron density height profiles to extents large enough to affect the propagation of radio waves over a large range of frequencies, including those used in HF telecommunications. The response of the D-region electron density to solar flare ionization can be reliability probed through remote sensing observations of VLF (3-30kHz) radio wave signals that propagate in the waveguide formed between the Earth’s surface and the lower ionosphere. By using a combination of solar flare multi-wavelength observations together with remote sensing of the ionospheric conditions we can probe the geophysical effects of flare emission. In this talk, I will present an overview of the solar flare effects on the ionospheric D-region and how we can utilize diverse data sets from both space- and ground- based observatories to help us build a better understanding of solar flares and their impacts on the Earth’s ionosphere.