Formation Of The Lyman Continuum During Solar Flares |
|
Shaun McLaughlin Submitted: 2023-01-05 04:19
The Lyman Continuum (LyC; <911.12Å) forms at the top of the chromosphere in the quiet-Sun, making LyC a powerful tool for probing the chromospheric plasma during solar flares. To understand the effects of non-thermal energy deposition in the chromosphere during flares, we analysed LyC profiles from a grid of field-aligned radiative hydrodynamic models generated using the RADYN code as part of the F-CHROMA project. The spectral response of LyC, the temporal evolution of the departure coefficient of hydrogen, b1, and the color temperature, Tc, in response to a range of non-thermal electron distribution functions, were investigated. The LyC intensity was seen to increase by 4-5.5 orders of magnitude during solar flares, responding most strongly to the non-thermal electron flux of the beam. Generally, b1 decreased from 102-103 to closer to unity during solar flares, indicating a stronger coupling to local conditions, while Tc increased from 8-9kK to 10-16kK. Tc was found to be approximately equal to the electron temperature of the plasma when b1 was at a minimum. Both optically thick and optically thin components of LyC were found in agreement with the interpretation of recent observations. The optically thick layer forms deeper in the chromosphere during a flare compared to quiescent periods, whereas the optically thin layers form at higher altitudes due to chromospheric evaporation, in low-temperature, high-density regions propagating upwards. We put these results in the context of current and future missions.
Authors: Shaun A. McLaughlin, Ryan O. Milligan, Graham S. Kerr, Aaron J. Monson, Paulo J. A. Simões, Mihalis Mathioudakis
Projects: None
|
Publication Status: Accepted for Publication in The Astrophysical Journal
Last Modified: 2023-01-05 13:47
|
 
 
 
 
|
|