Abstracts submitted by Matthieu Kretzschmar
The response of total solar irradiance to flares
M. Kretzschmar [1]; T. Dudok de Wit [2]; S. Mekaoui [3]; W. Schmutz [4]; J.F. Hochedez [1]; S. Dewitte [3]
[1] SIDC- Royal Observatory of Belgium; [2] LPCE / CNRS, Université d'Orléans, France; [3] Royal Meteorological Institute of Belgium; [4] PMOD/WRC, Switzerland
Solar flares are best seen in the EUV and X-ray spectral bands that usually characterize the corona; however they also affect the lower solar atmosphere and produce emission at longer wavelengths. Here we investigate the flare signatures at these longer wavelengths by using the total solar irradiance (TSI) measurements at high temporal resolution from the PMO and DIARAD sensors of the VIRGO experiment onboard SOHO. Using a conditional average that allows us to remove the fluctuations associated to p-modes, we show for the first time that there is a systematic increase of the TSI during flares belonging from x-ray class C to X. A systematic increase of visible irradiance is also found, demonstrating thus that white light flares are an intense and common feature of flares. We analyze the contribution of different spectral bands to the TSI increase and discuss the implications for flare energetics. These results are also of interests for Solar-Terrestrial relationships. |
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