Speaker
Description
Solar flares are the most powerful energy-release processes in the solar system. During the flare, a huge amount of energy is released in a relatively compact space. This can lead to the electron mean free path becoming comparable to the temperature gradient inside the loop and, therefore, to a violation of the local thermal transport approximation. In this case, the commonly used Spitzer-Harm approach is not applicable and thermal energy transport should be treated as non-local. In this regime of non-local thermal transport, suppression of heat flux and plasma preheating take place, which can strongly affect the dynamics of the plasma.
In this study, we use 1D hydrodynamic simulations to investigate how non-local thermal transport affects the thermodynamic (density-temperature) cycle of solar flares. We find that the non-local transport significantly modifies the cycle compared to the standard models of Spitzer-Harm and flux-limited local transport. In particular, during the energy release stage, the heat flux suppression leads to higher temperatures and lower densities at the loop apex. Additionally, heat fluxes result in slower chromospheric evaporation rates and, therefore, lower loop density in the case of non-local thermal transport. These effects may have observable consequences for coronal loop emission during and after flares, particularly in EUV and X-ray diagnostics.
