"Influence of magnetic configuration and RF heating on turbulence and confinement in the H1 Heliac and MAGPIE linear device," by Clive Michael (Australian National University)

Wednesday, September 26, 2018 - 1:00pm to 2:00pm
Plasma Seminars

Understanding the role of magnetic islands and ergodicity on confinement and turbulence is vitally important for understanding the suppression of edge localised modes via 3D fields in Tokamaks, and Stellarators.  The fixed, but finely tuneable magnetic configuration and relatively low beta of the H-1 Heliac Stellarator device a the Australian National University (ANU) is ideal for studying in detail the role of the magnetic configuration, including rational surfaces, magnetic shear, curvature and islands on turbulence at the plasma boundary. For example, changing the current in the helical coil can produce changes in rotational transform (twist) continuously, with low shear profiles, from about 1 to 1.5 and allows for detailed studies into the physics of Alfven waves.  When the rotational transform is close rational values, fluctuations increase, and pronounced global drops in the density can occur, which may be driven by fluctuation-induced transport, or by cross-field convective transport driven by poloidal asymmetries driven by localized ICRH heating on rational surfaces. RF-synchronized filtered imaging of line emission near the antenna has also revealed an edge-localized surface-wave characteristic of the slow-Alfven wave. Whilst H-1 has been shut-down and will be relocated to China, research is continuing on a linear Helicon-wave heated magnetic pinch device MAGPIE, primarily for plasma/wall interaction research, though some studies have been carried out on turbulence and flow dynamics.

Event Attachments: 
PAB 4-330