TY - JOUR

T1 - MHD equilibrium of a low-shear helical axis Heliotron

AU - Suzuki, Yasuhiro

AU - Nakamura, Yuji

AU - Kondo, Katsumi

AU - Hayashi, Takaya

AU - Lloyd, S. S.

AU - Gardner, H. J.

PY - 2003/6

Y1 - 2003/6

N2 - The HINT code is a three-dimensional MHD equilibrium calculation code which does not assume nested flux surfaces. This code has been applied to the study of helical system plasma and it has reproduced the phenomenon of magnetic islands in finite pressure equilibria. We modify the numerical scheme of HINT to make it more efficient. In particular, the calculation of the plasma pressure distribution is improved for the case of a low-shear stellarator like Heliotron J. Using the modified HINT code, we study the finite plasma pressure equilibria of Heliotron J plasmas. In the standard configuration of Heliotron J plasmas, the equilibrium with a peaked distribution of the plasma pressure has magnetic islands appearing at β ∼ 0.8%. When β ∼ 3%, the edge region of plasma is ergodized by the finite pressure effect and flux surfaces are broken. On the other hand, for a broad initial pressure distribution the island width is decreased, but the structure of magnetic field remains stochastic.

AB - The HINT code is a three-dimensional MHD equilibrium calculation code which does not assume nested flux surfaces. This code has been applied to the study of helical system plasma and it has reproduced the phenomenon of magnetic islands in finite pressure equilibria. We modify the numerical scheme of HINT to make it more efficient. In particular, the calculation of the plasma pressure distribution is improved for the case of a low-shear stellarator like Heliotron J. Using the modified HINT code, we study the finite plasma pressure equilibria of Heliotron J plasmas. In the standard configuration of Heliotron J plasmas, the equilibrium with a peaked distribution of the plasma pressure has magnetic islands appearing at β ∼ 0.8%. When β ∼ 3%, the edge region of plasma is ergodized by the finite pressure effect and flux surfaces are broken. On the other hand, for a broad initial pressure distribution the island width is decreased, but the structure of magnetic field remains stochastic.

UR - http://www.scopus.com/inward/record.url?scp=0038141198&partnerID=8YFLogxK

U2 - 10.1088/0741-3335/45/6/310

DO - 10.1088/0741-3335/45/6/310

M3 - Article

SN - 0741-3335

VL - 45

SP - 971

EP - 981

JO - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

IS - 6

ER -