Author(s): B. J. Frei, R. Bilato, O. Grover, W. Zholobenko, C. Angioni, M. Bergmann, P. Ulbl, F. Jenko, and the ASDEX Upgrade Team The origin of the difference in the high-confinement ($H$-mode) power threshold between favorable and unfavorable drift configurations in tokamaks—experimentally linked to a deeper radial electric field (${E}_{r}$) well in the former—remains unresolved. Using first-principles gyrokinetic simulations… [Phys. Rev. Lett. 137, 035103] Published Wed Jul 15, 2026