Speaker
Kerchung Shaing
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P1.1002.pdf
Banana kinetic equation and plasma transport in tokamaks
K. C. Shaing1, M. S. Chu1, S. A. Sabbagh2, and J. Seol3
1
National Cheng Kung University. Tainan City 701, Taiwan
2
Columbia University, New York, NY 10027, USA
3
National Fusion Research Institute, Daejeon 305-333, Korea
In a high temperature fusion relevant tokamak plasma, effects of finite banana width are
important to plasma dynamics. A banana kinetic equation that includes effects of finite
banana width is derived for both electrostatic and electromagnetic waves with frequencies
lower than the gyro-frequency, and the bounce frequency of the trapped particles [1,2]. The
radial wavelengths are assumed to be either comparable to or shorter than the banana width
but much wider than the gyro-radius. One of the consequences of the banana kinetics is that
the parallel component of the vector potential is not annihilated by the orbit averaging
process, and appears in the banana kinetic equation. The equation is solved to calculate
neoclassical quasilinear transport fluxes in the superbanana plateau, and other collisionality
regimes caused by both electrostatic and electromagnetic waves. The transport fluxes can be
used to model wave and chaotic magnetic field induced thermal particle or energetic alpha
particle losses in tokamaks. It is found that electrostatic turbulence induced transport losses
are reduced as a result of the banana kinetics. On the other hand, the parallel component of
the vector potential enhances losses when it is the sole transport mechanism. Especially, the
drift resonance can cause significant transport losses in the chaotic magnetic field in the
hitherto unknown low collisionality regimes. In general, it is the interference between the
electrostatic, and vector potentials, that ultimately determines whether the banana kinetics
enhances or improves the electromagnetic wave induced transport losses. The banana kinetics
also provides an isotope scaling. The implications on energetic alpha particle confinement in
ITER will be addressed.
Acknowledgement
This work was supported by Taiwan Ministry of Science and Technology under Grant No. 100-2112-M-006-
004-MY3.
References
[1] K C. Shaing, Phys. Plasmas 24, 122504 (2017)
[2] K. C. Shaing, M. S. Chu, S. A. Sabbagh, and J. Seol, accepted to appear in Phys. Plasmas 25 (2018)
