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Astrophysics Research Centre

School of Mathematics and Physics

Survey of 4 years of SDO/EVE observations of flare emission of H and He lines

  • Submitted by: Paulo Simões, University of Glasgow
  • Authors: P. Simões, L. Fletcher, N. Labrosse, G.S. Kerr
  • Session: Tuesday morning posters.

Solar flares have dramatic coronal manifestations but the bulk of the flare radiation comes from the denser lower atmosphere, being the main location of flare energy dissipation and radiation. The presence and many of the characteristics of a particular spectral line or continuum are determined mostly by the physical properties of the environment in which it is formed. Further insight into the flaring chromospheric plasma can be explored by employing models. Realistic simulations of observable parameters, such as spectral line profiles and continuum emission, dictate that non-equilibrium plasma modeling must be treated together with non-LTE radiation hydrodynamics. Comparing the output of such models and observational data we may be able to piece together the characteristic structure of a flaring atmosphere. The Extreme ultraviolet Variability Explorer (EVE), on board of the Solar Dynamics Observatory (SDO) launched in 2010, provides Sun-as-star spectral measurements in the EUV range 5-105 nm, with spectral resolution of 0.1 nm. We present our survey of the 4 years of EVE observations of solar flares and the results of our analysis of the irradiance of H Lyman beta, gamma and delta, He I 58.4 nm, and He II 30.4 nm emission lines. The flare emission of these lines is usually strong enough to be detected by EVE, even for weak GOES C-class events. The observed irradiances are compared to the output of non-LTE radiation hydrodynamics models to better constrain the model input and help to provide a better diagnostic of the plasma temperature, density and ionization of the different ions in the flaring chromosphere.

Click here to download pdf of eposter

public/hinode9/schedule/session-03p/v0070.txt · Last modified: 2015/09/30 08:00 by Mihalis Mathioudakis

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