Helimac a device for plasma turbulence investigations

Summary form only given. The new Helimac plasma device will produce a plasma that lends itself to the study of plasma turbulence. The configuration is accessible to straightforward theory of drift wave turbulence. The device is toroidal and has vertical and toroidal magnetic fields. Though it shares some features with a tokamak, it is substantially colder, lower density, and has a simpler magnetic configuration than do typical tokamaks. These properties make it easier to diagnose. The Helimac approximates an infinite cylinder with an MHD equilibrium that depends on a single radial variable. The magnetic field lines are helices of tight pitch. The configuration is intrinsically one dimensional with both magnetic curvature and shear. Flow shear can be externally applied and controlled. With an average radius of 1 m and height of 2 m, the size is very large compared with all scale lengths at the field of 0.1 T, temperatures of 10 eV, and densities of 10/sup 17/ m/sup -3/. The device to be built will feature continuous operation. The diagnostics will consist of full electrostatic probe diagnostics for complete characterization of the turbulence and of spectroscopic measurements of the induced flow field. The experimental design and plans for turbulence measurement and flow-shear suppression will be presented along with the conceptual design for the major diagnostics.