The Physics & Astronomy Colloquium Series presents Saskia Mordijck of William & Mary University, discussing "How to Fuel a Sun on Earth?" on March 27.

Abstract: Fusion energy promises to produce clean and safe electricity on a large scale, but it still faces some challenges. One technique to contain a fusion relevant plasma, with temperatures exceeding those of the sun, is to use strong magnetic fields in a device called a tokamak. The fusion gain in a tokamak is directly linked to the density of the plasma. However, due to the high temperatures, it impossible to fuel the core of the plasma directly and increase the core density. Without any direct fueling in the core of a tokamak, the plasma density is fully controlled by transport perpendicular to the confining magnetic field surfaces.

In this talk I will show how cross-field transport is dominated by turbulence in the plasma core by comparing experiments with existing models. These models capture how various types of turbulence influence transport and thus the density profile. While the density profile in the core is fully determined by turbulent transport, at the plasma edge, the picture is more complicated. At the edge of the tokamak, turbulent transport effects intermingle directly with fueling through ionization of the surrounding gas. The goal is to build a predictive transport model that captures the microscopic turbulence effects from the bottom (edge of the plasma) up (core plasma).