Speaker
Erika Strumberger
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/O2.108.pdf
CASTOR3D: linear stability studies for tokamak and stellarator
configurations
E. Strumberger, S. Günter
Max Planck Institute for Plasma Physics, 85748 Garching, Germany
Three-dimensional tokamak and stellarator equilibria are in the focus of present fusion re-
search. While stellarators are characterized by a complex 3D magnetic field topology, 3D toka-
maks are devices with weakly broken axisymmetry. Reasons for the asymmetry of tokamak
configurations are e.g. three-dimensional resistive wall structures which can reduce the growth
rates of external modes, and magnetic perturbation fields. The latter are applied to mitigate or
even to suppress edge localized modes (ELMs). The design of 3D fusion devices, as well as
the analysis and interpretation of the corresponding plasma discharges require appropriate nu-
merical tools that are able to handle their geometry. The newly developed, linear stability CAS-
TOR3D code [1] is such a tool. It is a hybrid of the linear stability CASTOR_3DW code [2] and
the resistive wall mode STARWALL code [3]. Numerous modifications and extensions of both
code parts led to a synergistic effect. The possible applications of the CASTOR3D code exceed
easily the possibilities of both of them. The code has a number of significant advantages. It al-
lows: (i) to choose between various kinds of flux coordinates, (ii) to perform ideal and resistive
stability studies for 3D equilibria, (iii) to take plasma inertia and resistive walls simultaneously
into account, (iv) to study the effects of plasma rotation and viscosity on the stability properties,
(v) to investigate vertical instabilities, and (vi) to deal with coils and multiply-connected wall
structures. The MPI parallelization of the code including the implementation of a parallel eigen-
value solver for non-hermitian eigenvalue problems (SLEPc [4]), allows an efficient solution of
large eigenvalue problems.
Stability studies demonstrating the large variety of possible application of the CASTOR3D
code will be presented for a 3D tokamak and a quasi-axisymmetric stellarator configuration.
References
[1] E. Strumberger and S. Günter,Nuclear Fusion 57, 016032 (2017)
[2] E. Strumberger et al., 38th EPS Conf. on Plasma Phys. (Strasbourg, France) vol 35G, (ECA) P5.082 (2011)
[3] P. Merkel and E. Strumberger (2015) http://arxiv.org/abs/1508.04911
[4] J.E. Romin et al., SLEPc users manual, Technical Report dsic-ii/24/02, Universidad Politecnica de Valencia
(2014), www.grycap.upv.es/slepc
