Authors: G. Dong, Z. Lin
Abstract: The effects of magnetic islands on electron
bootstrap current in toroidal plasmas are studied using
gyrokinetic simulations. The magnetic islands cause little changes
of the bootstrap current level in the banana regime because of
trapped electron effects. In the plateau regime, the bootstrap
current is completely suppressed at the island centers due to the
destruction of trapped electron orbits by collisions and the
flattening of pressure profiles by the islands. In the collisional
regime, small but finite bootstrap current can exist inside the
islands because of the pressure gradients created by large
collisional transport across the islands. Finally, simulation
results show that the bootstrap current level increases near the
island separatrix due to steeper local density gradients.
Submitted to: Nuclear Fusion
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