Global simulations of ion turbulence with magnetic shear reversal
This paper presents the results of three-dimensional fluid global simulations of electrostatic ion turbulence in tokamaks with reversed magnetic shear. It is found that a transport barrier appears at the location of magnetic shear reversal. This is due to a rarefaction of resonant surfaces in this region. For the same reason, the barrier is more pronounced when the minimum of the safety factor is a simple rational number. The barrier is broadened by velocity shear effects. It is also found that large-scale transport events hardly cross a transport barrier. Finally, a significant amount of toroidal rotation is generated by the turbulence. This rotation changes its sign at the position of magnetic shear reversal, as expected from a quasi-linear estimate of the Reynolds stress tensor.
Bibliographic Reference: An article published in: Physics of Plasmas, June 2001, Volume 8, Issue 6, pp. 2793-2803
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: http://ojps.aip.org/journal_cgi/dbt?KEY=PHPAEN&Volume=8&Issue=6
Record Number: 200215041 / Last updated on: 2002-07-29
Original language: en
Available languages: en