Date Thesis Awarded

5-2022

Access Type

Honors Thesis -- Access Restricted On-Campus Only

Degree Name

Bachelors of Science (BS)

Department

Physics

Advisor

Saskia Mordijck

Committee Members

David Armstrong

Pierre Clare

Abstract

In this project an optimization algorithm is developed to assist in the study of neutral and plasma densities in the plasma edge of tokamaks. The algorithm utilizes multivariate steepest descent to optimize matching of simulated electron-density profiles to experimental ones. In a standard tokamak, the edge is characterized by a region of open magnetic field lines, called the Scrape-Off Layer (SOL) which surrounds a well confined core region made of closed magnetic flux surfaces. Additional fuel is added in the form of neutral gas in the SOL and it is important to model how this interacts with the plasma. While electron densities and temperatures can be measured using the Edge Thomson Scattering Diagnostic, there are no direct measurements available of the neutral densities, which can vary substantially in magnitude as a function of location. This means that numerical methods must be used to find a full picture of neutral-plasma interactions. The Scrape Off Layer Plasma Simulations (SOLPS) program is a coupled plasma-neutral code used for modelling in the edge, and users can match Thomson scattering data to the simulation using boundary conditions and modification of radial transport coefficients. The optimization algorithm developed shortens the time it takes to find transport coefficients for given experimental plasma profiles. A brief overview is provided of work comparing neutral densities from C-mod and MAST, as well as possible future work in this area with the optimization algorithm.

Recommended Citation

Crouse, Gordon Jameson, "A Study of Transport in the SOL Region of Tokamaks" (2022). Undergraduate Honors Theses. William & Mary. Paper 1878.
https://scholarworks.wm.edu/honorstheses/1878