The Extreme ultraviolet Variability Experiment (EVE) instrument will be measuring the solar extreme ultraviolet (EUV) irradiance as part of the NASA Solar Dynamics Observatory (SDO) mission. These energetic photons in the EUV are the drivers for heating Earth's upper atmosphere and creating our
ionosphere (plasma in the atmosphere). The solar EUV radiation changes on all time scales with
changes being a factor of 2 to 1000 (wavelength dependent) over seconds-hours during flare events and
also long term changes by a factor of 2 to 10 over the 11-year solar cycle. These changes have impact
on our technology and society that includes our ability to track our satellites (e.g., satellite drag changes with atmospheric heating) and also causes degradation, and even disruption, of our communication and navigation (GPS) systems due to ionosphere responding to solar EUV variations.




