Speaker
Description
The existence of electromagnetic cylindrical modes is demonstrated in advanced tokamak scenarios with reversed magnetic shear. Unlike the pressure driven reverse shear Alfven eigenmode and ballooning/infernal mode, it is found that the triggering of such modes demands two essential conditions: a nonmonotonic safety factor and the kinetic compression effect of thermal particles. Accordingly, the resultant instability can be spontaneously excited by the presence of strong plasma nonuniformities and exhibits a mesoscale mode structure localized around the the minimum of safety factor. Owing to its long wavelength and electromagnetic nature, this instability can effectively induce the transport of both thermal and fast particles. Therefore, these cylindrical modes may have potentially serious implications for the sustainment of internal transport barrier, and also allow a precise determination of the radial location of the zero magnetic shear in tokamak experiments.
| Presentation type | Oral |
|---|
