It is shown that besides the ion orbit loss mechanism, which occurs in a region a-εtρp<r<a, the drift-orbit transport flux driven by the collisionless helically trapped particles can also drive the poloidal EE→×BE→ velocity in a region r<a-εtρp in stellarators. Here, r(a) is the minor (plasma) radius, εt is the toroidal amplitude of the magnetic field spectrum, E→(B→) is the electric (magnetic) field, and ρp is the poloidal ion gyroradius. The transport-flux-driven E→×B→ velocity can be triggered most efficiently by an increase of the ion temperature gradient. The theory is applied to the high-mode phenomenon observed in stellarators.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)