Response of the low ionosphere to X‐ray and Lyman‐α solar flare emissions

Citations Over TimeTop 21% of 2012 papers

Abstract

Using soft X‐ray measurements from detectors onboard the Geostationary Operational Environmental Satellite (GOES) and simultaneous high‐cadence Lyman‐α observations from the Large Yield Radiometer (LYRA) onboard the Project for On‐Board Autonomy 2 (PROBA2) ESA spacecraft, we study the response of the lower part of the ionosphere, the D region, to seven moderate to medium‐size solar flares that occurred in February and March of 2010. The ionospheric disturbances are analyzed by monitoring the resulting sub‐ionospheric wave propagation anomalies detected by the South America Very Low Frequency (VLF) Network (SAVNET). We find that the ionospheric disturbances, which are characterized by changes of the VLF wave phase, do not depend on the presence of Lyman‐α radiation excesses during the flares. Indeed, Lyman‐α excesses associated with flares do not produce measurable phase changes. Our results are in agreement with what is expected in terms of forcing of the lower ionosphere by quiescent Lyman‐α emission along the solar activity cycle. Therefore, while phase changes using the VLF technique may be a good indicator of quiescent Lyman‐α variations along the solar cycle, they cannot be used to scale explosive Lyman‐α emission during flares.

Related Papers

• → Overview of the Solar Activity During Solar Cycle 23(2006)50 cited
• → Solar activity during first six years of solar cycle 24 and 23: a comparative study(2014)20 cited
• → Study of intensive solar flares in the rise phase of solar cycle 23 and 24 and other activities(2016)15 cited
• → Comparison of I-ICME and M-ICME Fittings and In Situ Observation Parameters for Solar Cycles 23 and 24 and Their Influence on Geoeffectiveness(2023)2 cited