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Graduate Student Seminar -10/14/2016
"Breaking of Toroidal Symmetry and Rotation in ITER"
by Elizabeth Paul
Friday, October 14, 2016 -- 12:00 p.m.
Large Conference Room, 1207 Energy Research Facility
Advisor: Professor William Dorland
The ability to rapidly rotate is an essential property of tokamak plasmas, as rotation is known to suppress violent MHD modes and sheared rotation can reduce turbulent transport. While an ideal tokamak has perfect toroidal symmetry, this is impossible to engineer in practice. When the symmetry of the magnetic field is broken, the radial excursions of particles trapped by the mirror force does not necessarily vanish. One important consequence of nonaxisymmetry is a torque which acts to slow rotation, neoclassical toroidal viscosity (NTV).
The ITER collaboration aims to demonstrate fusion with the largest tokamak experiment. ITER's axisymmetry will be perturbed by the finite number of toroidal field coils and ferromagnetic components. We calculate neoclassical transport in ITER by solving a radially-local drift kinetic equation with models of ITER magnetic equilibrium. We present results which indicate that the NTV torque is comparable to the neutral beam torque near the edge and may result in a sheared rotation profile.
For additional information about the IREAP Graduate Student Seminars, contact Peter Megson.