Nuclear Fusion Award 2010 speech

[摘要] Following the suggestion of Earl Marmar in 1995, I installed a compact vonHamos type x-ray spectrometer (originally built with Elisabeth Rachlew and JanKallne) on a tangentially viewing port on the Alcator C-Mod tokamak. Thespectrometer views the plasma through a 2 cm diameter hole, and is tuned toH-like argon, suitable for passive measurement of the core toroidal rotationvelocity from the Doppler shift. It soon became evident that the rotation in OhmicL-mode discharges, while for the most part directed counter-current, depends in avery complicated fashion on plasma parameters, notably the electron density,current and magnetic configuration. The rotation can even flip sign for almost noapparent reason! In Ohmic and ion cyclotron range of frequencies (ICRF) heatedH-mode plasmas the rotation is in the co-current direction and has a relativelysimple dependence on plasma parameters, proportional to the stored energynormalized to the current. Rotation velocities as high as 130 km s−1 have beenobserved without external momentum input. In dimensionless terms this intrinsic(or spontaneous rotation) depends on the normalized plasma pressure. Theassociation of toroidal rotation with plasma pressure in ICRF H-modes was firstobserved by Lars-Goran Eriksson in JET discharges. Similar results weresubsequently reported for Tore Supra enhanced confinement plasmas.