TY - JOUR
T1 - Kinetic theory of helical instabilities in a cylindrical tokamak
AU - Inoue Itoh, S.
AU - Itoh, K.
PY - 1981/1
Y1 - 1981/1
N2 - The kinetic theory of the drift-tearing mode in a finite-β, collisionless inhomogeneous cylindrical tokamak is investigated. It is found that 1) when the density is low, the kinetic drift-tearing modes are unstable whereas they become stabilized as the density increases, 2) the medium-m (poloidal mode number) modes have a smaller growth rate, and 3) the electron temperature gradient further stabilizes these modes. Because of the magnetic shear and the finite β value, the outgoing drift wave is associated with the tearing mode, and hence the ion Landau damping stabilizes the mode when β increases. The local current density is found to be crucial for the instability. It is noted that the stability criterion for the MHD tearing mode, [formatted text] is the jump of the logarithmic derivative of Br across the mode rational surface), is lo longer valid for kinetic tearing mode. - For future tokamak parameters, low- and medium-m (2 ≤m ≲ 50) kinetic drift-tearing modes are found to be stable in cylindrical geometry.
AB - The kinetic theory of the drift-tearing mode in a finite-β, collisionless inhomogeneous cylindrical tokamak is investigated. It is found that 1) when the density is low, the kinetic drift-tearing modes are unstable whereas they become stabilized as the density increases, 2) the medium-m (poloidal mode number) modes have a smaller growth rate, and 3) the electron temperature gradient further stabilizes these modes. Because of the magnetic shear and the finite β value, the outgoing drift wave is associated with the tearing mode, and hence the ion Landau damping stabilizes the mode when β increases. The local current density is found to be crucial for the instability. It is noted that the stability criterion for the MHD tearing mode, [formatted text] is the jump of the logarithmic derivative of Br across the mode rational surface), is lo longer valid for kinetic tearing mode. - For future tokamak parameters, low- and medium-m (2 ≤m ≲ 50) kinetic drift-tearing modes are found to be stable in cylindrical geometry.
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U2 - 10.1088/0029-5515/21/1/001
DO - 10.1088/0029-5515/21/1/001
M3 - Article
AN - SCOPUS:0019515979
VL - 21
SP - 3
EP - 13
JO - Nuclear Fusion
JF - Nuclear Fusion
SN - 0029-5515
IS - 1
ER -