Speaker
W. Guo
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P1.1054.pdf
Numerical studies of plasmoids during the nonlinear evolution of double
tearing modes in slab and cylindrical geometry
W. Guo1, J. Ma1, Z. Yu1 ,Q. Yu2
1
Institute of Plasma Physics, Chinese Academy of Science, Hefei, Anhui , China
2Max-Planck-Institut für Plasmaphysik, 85748 Garching, Germany
Email:wfguo@ipp.ac.cn
Double tearing mode (DTM) is an important kind of magnetohydrodynamics (MHD)
instability that often occurs with reversed central magnetic shear configuration in tokamak
discharges. A nonlinear MHD code based on a conservative perturbed MHD model by
splitting primary variables in original MHD equations into equilibrium part and perturbed
part has been developed. The nonlinear evolution of double tearing mode in slab and
cylindrical geometry is numerically investigated in high Lundquist number regime. The
onset of the secondary and tertiary islands (plasmoids) due to the tearing unstable current
sheets formed during the fast reconnection phase and a new nonlinear evolution process
characterized by two fast reconnection phase are investigated and discovered. More effects,
including the flow, guiding field, viscosity etc. are under way. In cylindrical geometry
plasmoid generations different from slab geometry during the nonlinear DTM evolution are
observed. The details will be presented.
(a) (b)
Plasmoids during the nonlinear evolution of DTM in high Lundquist number regime:(a)
Multiple (five) secondary islands formation in nonlinear evolution of double tearing mode
with equilibrium current sheets distance y0=0.2,(b)A typical picture of a new quasi-stationary
characterized as two pairs of coexisting islands with well preserved symmetry.
*This work is supported National Key R&D Program of China under Grant No.
2017YFE0300402 and the National Natural Science Foundation of China under Grant Nos.
11475219,11775268.
