213 citations · 261 across the 14 of their papers we have counts for
14 papers
Compact quasiaxisymmetric stellarators, a near axisymmetric theory
Wrick Sengupta, Rogerio Jorge, Nikita Nikulsin +4
We develop a theory of ridges in compact stellarators with quasiaxisymmetry (QA). The equilibrium with finite plasma currents and pressure is modeled by ideal magnetohydrostatics (…
On the Shafranov shift in stellarators
Per Helander, Nikita Nikulsin
As first shown by Shafranov, toroidal plasmas in magnetohydrodynamic equilibrium tend to expand in major radius when the pressure is increased. Here, an average measure of the resu…
Optical analogy for stellarators: Ridges as caustics and coils as singularities
Wrick Sengupta, Stefan Buller, Rogerio Jorge +7
A common feature of most numerically optimized stellarator geometries is the presence of sharp ridges on outer flux surfaces, irrespective of the rotational transform. Despite thei…
Periodic Korteweg-de Vries soliton potentials generate quasisymmetric magnetic field strength in a finite plasma-beta equilibrium
W. Sengupta, R. Madan, S. Buller +6
Quasisymmetry (QS) is a hidden symmetry of the magnetic field strength, B, that enables effective confinement of charged particles in a fully three-dimensional (3D) toroidal plasma…
A class of high-beta, large-aspect-ratio quasiaxisymmetric Palumbo-like configurations
Andrew Brown, Wrick Sengupta, Nikita Nikulsin +1
The space of high-beta, approximately quasiaxisymmetric, large-aspect-ratio stellarator configurations is explored using an inverse coordinate approach and a quadratic polynomial a…
A Grad-Shafranov model for compact quasisymmetric stellarators
Nikita Nikulsin, Wrick Sengupta, Stefan Buller +1
A Grad-Shafranov equation (GSE) valid for compact quasisymmetric stellarators is derived by an asymptotic expansion around a vacuum field carried to first order. We obtain an equat…
An asymptotic Grad-Shafranov equation for quasisymmetric stellarators
Nikita Nikulsin, Wrick Sengupta, Rogerio Jorge +1
A first-order model is derived for quasisymmetric stellarators where the vacuum field due to coils is dominant, but plasma-current-induced terms are not negligible and can contribu…
Nonlinear MHD modeling of soft limits in W7-AS
Rohan Ramasamy, Ksenia Aleynikova, Nikita Nikulsin +5
An important question for the outlook of stellarator reactors is their robustness against pressure driven modes, and the underlying mechanism behind experimentally observed soft $β…
Asymptotic quasisymmetric high-beta 3D MHD equilibria near axisymmetry
W. Sengupta, N. Nikulsin, R. Gaur +1
Quasisymmetry (QS), a hidden symmetry of the magnetic field strength, is known to support nested flux surfaces and provide superior particle confinement in stellarators. In this wo…
Periodic Korteweg-de Vries soliton potentials generate quasisymmetric magnetic fields
W. Sengupta, N. Nikulsin, S. Buller +6
Quasisymmetry (QS) is a hidden symmetry of the magnetic field strength, B, that effectively confines charged particles in a three-dimensional toroidal plasma equilibrium. Here, we…
JOREK3D: An extension of the JOREK nonlinear MHD code to stellarators
Nikita Nikulsin, Rohan Ramasamy, Matthias Hoelzl +4
Although the basic concept of a stellarator was known since the early days of fusion research, advances in computational technology have enabled the modelling of increasingly compl…
Testing of the new JOREK stellarator-capable model in the tokamak limit
Nikita Nikulsin, Matthias Hoelzl, Alessandro Zocco +2
In preparation for extending the JOREK nonlinear MHD code to stellarators, a hierarchy of stellarator-capable reduced and full MHD models has been derived and tested. The derivatio…
The JOREK non-linear extended MHD code and applications to large-scale instabilities and their control in magnetically confined fusion plasmas
M Hoelzl, GTA Huijsmans, SJP Pamela +50
JOREK is a massively parallel fully implicit non-linear extended MHD code for realistic tokamak X-point plasmas. It has become a widely used versatile code for studying large-scale…
A three-dimensional reduced MHD model consistent with full MHD
Nikita Nikulsin, Matthias Hoelzl, Alessandro Zocco +2
Within the context of a viscoresistive magnetohydrodynamic (MHD) model with anisotropic heat transport and cross-field mass diffusion, we introduce novel three-term representations…