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labmag_epr2014_talk.pdf2014-08-06 13:18:31Mike Mauel

Discovery Fusion Energy Science using a Superconducting Laboratory Magnetosphere

Author: Mike Mauel
Requested Type: Consider for Invited
Submitted: 2014-05-28 12:07:19

Co-authors: D. Garnier, J. Kesner, T. M. Roberts

Contact Info:
Columbia University
500 West 120th Street
New York, NY   10027
USA

Abstract Text:
Laboratory magnetospheres are facilities for discovery plasma science and for controlled plasma experiments in the magnetic geometry relevant to planetary magnetospheres. During the past decade, we have discovered how to create, measure, and control the high-temperature plasma trapped in three large laboratory magnetospheres, at Columbia University, MIT, and the University of Tokyo. With it's high-field superconducting magnets, the Levitated Dipole Experiment (LDX) at MIT is the world's largest laboratory magnetosphere and, also, our nation’s only steady-state facility for the study of toroidally confined plasma.

This presentation reviews these experiments and highlights investigations that have changed the way we think about the toroidal confinement of high temperature plasma. Without a toroidal field, plasma pressure can be sustained equal to the local magnetic pressure (β ~ 1). Without magnetic shear, interchange and entropy modes dominate plasma dynamics, in contrast to the ballooning, gradient drift, and current-driven modes found in tokamaks. When plasma is trapped by a levitated dipole magnet, turbulence naturally and continuously drives plasma self-organization and maintains steep plasma profiles that approach a state of minimum entropy production.

Important research opportunities exist for the LDX facility, but these experiments will require operating funds in order to purchase liquid helium for the superconducting magnets, to support engineering, scientific, technical staff, and to install improved plasma diagnostics and the RF antenna needed to access higher plasma density. Higher plasma density will allow laboratory investigations of (i) magnetospheric Alfvén wave dynamics at high plasma β, (ii) finite ion temperature modifications to bounce-averaged gyrokinetics and turbulent self-organization, and (iii) steady-state toroidal magnetic confinement at high power using heating sources already located at LDX.

Characterization: 1.0

Comments:

Workshop on Exploratory Topics in Plasma and Fusion Research (EPR) and US-Japan Compact Torus (CT) Workshop
August 5-8, 2014
Madison, Wisconsin

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