Axial shear instability in a "tachion" region

Tsidulko, YA
Marji, E
Bilikmen, S
Mirnov, VV
Cakir, S
Oke, G
Plasma axial-shear flow instability arises due to a variation in an equilibrium E x B rotation along the axial direction in which the magnetic field is aligned. The two fluid MHD equations for incompressible perturbation (taking into account the FLR effects) being treated in WKB approximation in transversal direction yield one scalar Klein-Gordon type equation with one-dimensional effective potential U(s) and effective mass on(s). Only axisymmetric, paraxial geometry is analyzed in order to separate the desired effects from the effects related to a variation in cross-sectional shape of the magnetic flux tube. In this work the effective potential was considered for a semi-infinite bounded plasma, first in the form of a square well for analytical study and then in a linear nature to study in the so called "tachion" region. Growth rates as a function of the potential well depth and other parameters were calculated. The cases where effective mass is real and imaginary "tachion" regime were considered. The results obtained are interesting for the stability problem of such open devices as GDT, GAMMA-10 AMBAL-M and the scrape-off layer in tokamak divertors.


Exact and FDM solutions of 1D MHD flow between parallel electrically conducting and slipping plates
Arslan, Sinem; Tezer, Münevver (Springer Science and Business Media LLC, 2019-08-01)
In this study, the steady, laminar, and fully developed magnetohydrodynamic (MHD) flow is considered in a long channel along with the z-axis under an external magnetic field which is perpendicular to the channel axis. The fluid velocity u and the induced magnetic field b depend on the plane coordinates x and y on the cross-section of the channel. When the lateral channel walls are extended to infinity, the problem turns out to be MHD flow between two parallel plates (Hartmann flow). Now, the variations of u...
Tezer, Münevver; ARIEL, PD (Wiley, 1988-01-01)
Flow of viscous, incompressible, electrically conducting fluid, driven by imposed electric currents has been investigated in the presence of a transverse magnetic field. The boundary perpendicular to the magnetic field is perfectly conducting partly along its length. Three cases have been considered: a) flow in the upper half plane when the boundary to the right of origin is insulating and that to the left is perfectly conducting, b) flow in the upper half plane when a finite length of the boundary is perfe...
Oscillation criteria for third-order nonlinear functional differential equations
AKTAŞ, MUSTAFA FAHRİ; Tiryaki, A.; Zafer, Ağacık (Elsevier BV, 2010-07-01)
In this work, we are concerned with oscillation of third-order nonlinear functional differential equations of the form
Finite element study of biomagnetic fluid flow in a symmetrically stenosed channel
Turk, O.; Tezer, Münevver; Bozkaya, Canan (Elsevier BV, 2014-03-15)
The two-dimensional unsteady, laminar flow of a viscous, Newtonian, incompressible and electrically conducting biofluid in a channel with a stenosis, under the influence of a spatially varying magnetic field, is considered. The mathematical modeling of the problem results in a coupled nonlinear system of equations and is given in stream function-vorticity-temperature formulation for the numerical treatment. These equations together with their appropriate boundary conditions are solved iteratively using the ...
Error estimates for space-time discontinuous Galerkin formulation based on proper orthogonal decomposition
Akman, Tuğba (Informa UK Limited, 2017-01-01)
In this study, proper orthogonal decomposition (POD) method is applied to diffusion-convection-reaction equation, which is discretized using spacetime discontinuous Galerkin (dG) method. We provide estimates for POD truncation error in dG-energy norm, dG-elliptic projection, and spacetime projection. Using these new estimates, we analyze the error between the dG and the POD solution, and the error between the exact and the POD solution. Numerical results, which are consistent with theoretical convergence ra...
Citation Formats
Y. Tsidulko, E. Marji, S. Bilikmen, V. Mirnov, S. Cakir, and G. Oke, “Axial shear instability in a “tachion” region,” FUSION TECHNOLOGY, pp. 304–307, 1999, Accessed: 00, 2020. [Online]. Available: