Speaker
Mr
Min Xu
(China)
Description
We report the first experimental evidence that turbulent eddies mediate the particle, momentum and vorticity transport at the edge of a tokamak plasma so as to amplify the shear layer at the last closed flux surface (LCFS). We find that turbulent eddies with relative negative vorticity (opposite to B field) and positive azimuthal momentum (electron-diamagnetic drift direction) are drawn from both sides of and move towards the location r-r_LCFS=-1cm ; while eddies with relative positive vorticity (i.e. parallel to the B field) and negative azimuthal momentum (ion-diamagnetic drift direction) propagate away from this location towards to the core and scrape-off layer (SOL) plasma regions. Thus negative vortices act to concentrate positive momentum into the region just inside the LCFS, and plasma in this region acquires a ExB drift in the electron drift direction while plasma deeper within and out in the SOL has an ExB drift in the ion diamagnetic direction. This turbulent eddy-mediated particle, momentum, and polarization charge transport process is shown in figure 1 by the conditionally averaged quantities inferred by using vorticity as the reference. Notice that eddies with positive and negative vorticity are associated with different signs of density fluctuation and transport in different directions inside the LCFS at r-r_LCFS=-2cm and in the SOL at r-r_LCFS=1cm .
Country or International Organization of Primary Author
China
Collaboration (if applicable, e.g., International Tokamak Physics Activities)
University of California, San Diego
Primary author
Mr
Min Xu
(China)
Co-authors
Dr
Christopher Holland
(University of California San Diego)
Prof.
George TYNAN
(University of California San Diego)
Prof.
Jiaqi Dong
(Southwestern Institute of Physics)
Dr
Jonathan Yu
(University of California San Diego)
Mr
Jun Cheng
(Southwestern Institute of Physics)
Prof.
Kaijun Zhao
(Southwestern Institute of Physics)
Prof.
Laizhong Cai
(Southwestern Institute of Physics)
Prof.
Longwen Yan
(Southwestern Institute of Physics)
Dr
Nicolas Fedorczak
(University of california san diego)
Prof.
Patrick Diamond
(University of California San Diego)
Dr
Peter MANZ
(University of california san diego)
Prof.
Qingwei Yang
(Southwestern Institute of Physics)
Dr
Saikat Chakraborty Thakur
(University of California San Diego)
Mr
Wenyu Hong
(Southwestern Institute of Physics)
Mr
Wulu zhong
(Southwestern Institute of Physics)
Prof.
Xianming SONG
(Southwestern Institute of Physics)
Prof.
Xuantong Ding
(Southwestern Institute of Physics)
Prof.
Xuru Duan
(Southwestern Institute of Physics)
Prof.
Yong Liu
(Southwestern Institute of Physics)
Dr
Yuan Huang
(Southwestern Institute of Physics)
Dr
Zhongbing Shi
(Southwestern Institute of Physics)
