Time:Friday, May 17, 01:00pm
Venue:Rm.413, Bld.11#, Yuquan Campus
Title: Sawtooth crashes with non-monotonical q-profile
Speaker: X. Wang (王鑫)
Abstract: Mode structures with higher harmonics before sawtooth crashes are commonly observed inside and/or near the q =1 flux surface during localized electron cyclotron resonance heating and current drive (ECRH/CD) in KSTAR. In this talk, we present our simulation study of the sawtooth crash with non-monotonical q-profile by using CLT. With proper chosen locations and separations of triple q=1 resonance surfaces, it is found that the mode structure with a higher harmonic mode is emerged first, then the lower n mode gradually develops and takes over. Just before sawtooth crash, the m/n=1/1 mode becomes dominant as in a usual sawtooth crash. Our result qualitatively reproduces the time evolution of the mode structure observed in KSTAR.