MIDIT OFD CATS Modelling, Nonlinear Dynamics Optics and Fluid Dynamics Chaos and Turbulence Studies and Irreversible Thermodynamics Risø National Laboratory Niels Bohr Institute and Technical University of Denmark Building 128 Department of Chemistry Building 321 P.O. Box 49 University of Copenhagen DK-2800 Lyngby DK-4000 Roskilde DK-2100 Copenhagen Ø Denmark Denmark Denmark
by Thomas Sunn Pedersen
Columbia University
Thursday, March 15, 2001, 14.00 h
at OFD Meeting Room, Building 130, Risø National Laboratory
Abstract: A new basic plasma physics experiment, called the Columbia Non-neutral Torus (CNT) is being designed at Columbia University. In CNT, we will study pure electron plasmas in two fundamentally different toroidal magnetic geometries - a pure toroidal field, with closed field lines and no flux surfaces, and a stellarator configuration, which has nested closed flux surfaces even in the absence of plasma current. If successful, this will be the first pure electron plasma experiment in a stellarator geometry, and one of the first electron plasma experiments in a pure toroidal field. By starting out with a pure electron plasma and adding neutral gas, we may also be able to create a non-neutral electron-ion plasma, which would be strongly rotating. In recent years, fusion experiments have shown that strong rotation and shear can have a profound effect on plasma confinement, so there is significant interest in studying strongly rotating electron-ion plasmas. The stellarator geometry will be quasi-helical, which minimizes drift excursions, and hence, allows us to confine high energy particles at a relatively low magnetic field strength. This ability to confine energetic particles may allow us to efficiently trap positrons in the CNT device. We may also be able to conduct the first laboratory studies of confined positron-electron plasmas. In this presentation, we will describe the physics issues which we plan to address in CNT, and discuss the preliminary design of the experiment.