Abstract Details
Abstracts
Author: Silvia Trinczek
Requested Type: Poster
Submitted: 2026-03-18 10:02:53
Co-authors: F. I. Parra
Contact Info:
Princeton University / PPPL
100 Stellarator Rd
Princeton, 08540
United States
Abstract Text:
Transport barriers in tokamaks, such as the pedestal, are regions of strong gradients and reduced turbulence where neoclassical transport can play a dominant role. However, standard neoclassical transport theory assumes that the gradient length scales of density, temperature, and potential are of the order of the system size. In the pedestal, gradient length scales are much shorter and are measured to be of the order of the ion poloidal gyroradius. We present an extension of neoclassical theory that is applicable in transport barriers of large aspect ratio tokamaks. In strong gradient regions, density, electric potential, mean parallel flow, and ion temperature are shown to no longer be flux functions. Instead, they have a small but important poloidally varying piece that modifies the transport equations to lowest order. This introduces a nonlinearity in the transport problem through the coupling with quasineutrality that yields multiple co-existing solutions when solving for the plasma profiles. The different solutions could be connected to low and high transport states and jumps between solutions could be an indication of H-L back-transitions.
Characterization: 2.0
Comments: