Theoretical prediction of [tau]E and [beta]⁻ in a large aspect ratio LDX

The Levitated Dipole Experiment (LDX) is a novel experiment to study the confinement of a high-temperature plasma in the magnetic field of a superconducting ring of wire. The levitated magnet produces a poloidal closed-line magnetic field characteristic of an ideal point dipole or a hard core Z-pinch magnetic configuration. The point dipole and hard core Z-pinch configurations share similar physics and may be respectively considered to be the zero and large aspect ratio approximations to LDX. The present work focuses on a hard-core Z-pinch magnetic configuration. An analysis is presented that theoretically predicts (1) the maximum pressure p., (2) the energy confinement time TE and (3) the average beta / by solving a proposed self-consistent model of plasma. The model makes the optimistic assumption that transport is purely classical in the region of the profile that is magnetohydrodynamically (MHD) stable against interchange modes. For the interchange unstable region, a quasilinear MHD transport model is developed. The analysis of MHD quasilinear transport starts with an assessment of stability corrections due to axial flows. The axial flows are taken as an approximation to the LDX toroidal flows, expected to appear due to non-ambipolar transport. It is shown that the subsonic axial flows create only negligible correction to the plasma stability and the MHD transport analysis is performed for a static plasma. The evolution of the particle density, energy and magnetic field in the MHD unstable region is investigated using the quasilinear approximation. The exact transport equations are derived for a static plasma in the hard core Z-pinch magnetic configuration. The equations are generalized to an arbitrary axisymmetric closed-filed line magnetic configuration.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Nuclear Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Kouznetsov, Alexei (Alexei Alexey)

Advisor dc:contributor.advisor

• Jeffrey P. Freidberg and Jay Kesner.

• Nuclear Science and Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/41292

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/41292