Grant M. Bodner

High Confinement Mode and Edge Localized Mode Characteristics in a Near-Unity Aspect Ratio Tokamak

Tokamak experiments at near-unity aspect ratio A≲1.2 offer new insights into the self-organized H-mode plasma confinement regime. In contrast to conventional A∼3 plasmas, the L-H power threshold P_{LH} is ∼15× higher than scaling predictions, and it is insensitive to magnetic topology, consistent with modeling. Edge localized mode (ELM) instabilities shift to lower toroidal mode numbers as A decreases. These ultralow-A operations enable heretofore inaccessible J_{edge}(R,t) measurements through an ELM that show a complex multimodal collapse and the ejection of a current-carrying filament.

H-mode plasmas at very low aspect ratio on the Pegasus Toroidal Experiment

H-mode is obtained at

Noninductively Driven Tokamak Plasmas at Near-Unity Toroidal Beta

A\sim 1.2

Control and automation of the Pegasus multi-point Thomson scattering system

in the Pegasus Toroidal Experiment via Ohmic heating, high-field-side fueling, and low edge recycling in both limited and diverted magnetic topologies. These H-mode plasmas show the formation of edge current and pressure pedestals and a doubling of the energy confinement time to

Public Data Set: Control and Automation of the Pegasus Multi-point Thomson Scattering System

{ {H}_{98y,2}}\sim 1

Public Data Set: Non-Inductively Driven Tokamak Plasmas at Near-Unity Toroidal Beta

. The L–H power threshold