Study of the impact of ion temperature perturbations on the inferences of incremental electron thermal diffusivity

In the study of electron perturbative heat transport, electron incremental diffusivity, χ^inc_e , is often used in validating transport models. Experimental χ^inc_e are typically inferred by assuming that a perturbation in the electron heat flux only has a dependence on the ∇Te, not ∇Ti (Creely et al., 2016). However, multi-scale simulation work has showed that, in plasmas with very stiff ITG transport, even small changes in ∇Ti can impact the electron heat flux (Howard et al., 2018). We take profiles from an electron-heated L-mode plasma on ASDEX Upgrade as the initial condition in our simulations, and apply perturbations. With the TGLF transport model, we find ∇Ti has a similarly strong effect to ∇Te on the electron heat flux regardless of the direction of propagation for the dominant long-wavelength instability. Work is on-going to use time-dependent, self-consistent transport modeling with TRANSP and ASTRA to test the impact of the ion temperature evolution on calculated χ^inc_e . We perform scans of the strength of the heat pulses and the plasma conditions to test the regimes in which ignoring the ion channel in the inference of χ^inc_e is a valid approach.