  During solar flares plasma is typically heated to very high temperatures, and
the resulting redistribution of energy via thermal conduction is a primary
mechanism transporting energy throughout the flaring solar atmosphere. The
thermal flux is usually modeled using Spitzer's theory, which is based on local
Coulomb collisions between the electrons carrying the thermal flux and those in
the background. However, often during flares, temperature gradients become
sufficiently steep that the collisional mean free path exceeds the temperature
gradient scale size, so that thermal conduction becomes inherently non-local.
Further, turbulent angular scattering, which is detectable in nonthermal widths
of atomic emission lines, can also act to increase the collision frequency and
so suppress the heat flux. Recent work by Emslie & Bian (2018) extended
Spitzer's theory of thermal conduction to account for both non-locality and
turbulent suppression. We have implemented their theoretical expression for the
heat flux (which is a convolution of the Spitzer flux with a kernel function)
into the RADYN flare-modeling code and performed a parameter study to
understand how the resulting changes in thermal conduction affect flare
dynamics and hence the radiation produced. We find that models with reduced
heat fluxes predict slower bulk flows, less intense line emission, and longer
cooling times. By comparing features of atomic emission lines predicted by the
models with Doppler velocities and nonthermal line widths deduced from a
particular flare observation, we find that models with suppression factors
between 0.3 to 0.5 relative to the Spitzer value best reproduce observed
Doppler velocities across emission lines forming over a wide range of
temperatures. Interestingly, the model that best matches observed nonthermal
line widths has a kappa-type velocity distribution function.
