Neoclassical polarization drift of collisionless single ions in a sheared radial electric field in a tokamak magnetic geometry
- Department of Physics, Korea Advanced Institute of Science and Technology, Yusong-Ku, Daejon, 305-701 (Korea, Republic of)
Neoclassical polarization drift is known to play critical role in the dynamical behavior of a sheared radial electric field E{sub r} in a toroidal confinement device. However, basic studies on the effect of radial electric shear on neoclassical polarization drift have not yet appeared in the literature. In the present report, the neoclassical polarization drift speed V{sub NP} of collisionless single ions is studied using a guiding-center code in a time-varying, spatially sheared E{sub r} in a realistic tokamak geometry. It is found numerically that the V{sub NP} for single ions is not only a function of the time derivative {partial_derivative}E{sub r}/{partial_derivative}t, but also a strong function of the radial shear {delta}r{partial_derivative}E{sub r}/{partial_derivative}r if the shear length is on the same order as the ion banana width {delta}r. Comparison with an analytic investigation reveals that this effect is simply due to the finite banana modification to the orbital average E{sub r}. An approximate analytic formula has been presented for collisionless single banana ions in a conventional tokamak magnetic geometry. The trapped-passing boundary layer physics is not treated.
- OSTI ID:
- 20782445
- Journal Information:
- Physics of Plasmas, Vol. 13, Issue 1; Other Information: DOI: 10.1063/1.2158151; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Strong drifts effects on neoclassical transport
Neoclassical rotation velocities in multispecies plasmas