Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 46
Book Description
An Analytic Solution of High. Beta. Equilibrium in a Large Aspect Ratio Tokamak
Author: An Analytic Solution of High. Beta. Equilibrium in a Large Aspect Ratio Tokamak
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 46
Book Description
An analytic solution of the high? (?{bar?}{sub p} -?q2/? {much gt} 1) equilibrium of a large aspect ratio tokamak is presented. Two arbitrary flux functions, the pressure profile p and the safety factor profile q , specify the equilibrium. The solution splits into two asymptotic regions: the core region where? is a function of the major radius alone and a narrow boundary layer region adjoining the conducting wall. The solutions in the two regions are asymptotically matched to each other. For monotonic pressure profiles, the Shafranov shift is equal to the minor radius. For? much bigger than one, the solution contains a region (in place of the magnetic axis) of zero magnetic field and constant pressure. At high? the quantity?{sub I}, which is essentially proportional to the pressure over the total current squared, is largely independent of pressure. We discuss the important ramifications of limited?{sub I} for high? reactors. Generalizations to shaped cross sections and hollow pressure profiles are outlined. We also consider the problem of equilibrium reconstruction in the high {beta} regime. 8 refs., 7 figs.
Free Boundary, High Beta Equilibrium in a Large Aspect Ratio Tokamak with Nearly Circular Plasma Boundary
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
An analytic solution is obtained for free-boundary, high-beta equilibria in large aspect ratio tokamaks with a nearly circular plasma boundary. In the absence of surface currents at the plasma-vacuum interface, the free-boundary equilibrium solution introduces constraints arising from the need to couple to an external vacuum field which is physically realizable with a reasonable set of external field coils. This places a strong constraint on the pressure profiles that are consistent with a given boundary shape at high[epsilon][beta][sub p]. The equilibrium solution also provides information on the flux surface topology. The plasma is bounded by a separatrix. Increasing the plasma pressure at fixed total current causes the plasma aperture to decrease in a manner that is described.
Begravelsesritual
Author: Free Boundary, High Beta Equilibrium in a Large Aspect Ratio Tokamak with Nearly Circular Plasma Boundary
Author: Hong QinEnergy Research Abstracts
Author: Analytic, High-beta Solutions of the Helical Grad-Shafranov Equation
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 20
Book Description
We present analytic, high-beta ([beta] ≈ O(1)), helical equilibrium solutions for a class of helical axis configurations having large helical aspect ratio, with the helix assumed to be tightly wound. The solutions develop a narrow boundary layer of strongly compressed flux, similar to that previously found in high beta tokamak equilibrium solutions. The boundary layer is associated with a strong localized current which prevents the equilibrium from having zero net current.
A Tokamak Equilibrium with Arbitrary Aspect Ratio
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 13
Book Description
A general analytical solution of the Grad-Shafranov equation is presented. It allows the simulation of plasmas with elongation and triangularity, with an independent choice of pressure and plasma current. A numerical computed fit to families of such solutions allows the direct computation of the poloidal flux function [Psi](R, Z) from a parametric description of the plasma given by aspect ratio A, elongation [kappa], triangularity [delta], size (i.e. major radius), plasma beta poloidal [beta]{sub pol}, and plasma current I{sub p}.
Stability of High. Beta. Large Aspect Ratio Tokamaks
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 27
Book Description
High [beta]([beta]{much gt} [epsilon]/q2) large aspect ratio ([epsilon] {much gt} 1) tokamak equilibria are shown to be always stable to ideal M.H.D. modes that are localized about a flux surface. Both the ballooning and interchange modes are shown to be stable. This work uses the analytic high [beta] large aspect ratio tokamak equilibria developed by Cowley et.al., which are valid for arbitrary pressure and safety factor profiles. The stability results make no assumption about these profiles or the shape of the boundary. 14 refs., 4 figs.
Author: K. Okano