Theory of continuum damping of toroidal Alfven Eigenmodes in finite-[beta] tokamaks

Technical Report · Sat May 01 00:00:00 EDT 1993

DOI:https://doi.org/10.2172/7368751· OSTI ID:7368751

Zonca, F; Chen, Liu

We have formulated a general theoretical approach for analyzing two-dimensional structures of high-n Toroidal Alfven Eigenmodes (TAE) in large aspect-ratio, finite-[beta] tokamaks. Here, n is the toroidal wave number and [beta] is the ratio between plasma and magnetic pressures. The present approach generalizes the standard ballooning-mode formalism and is capable of treating eigenmodes with extended global radial structures as well as finite coupling between discrete and continuous spectra. Employing the well-known (s,[alpha]) model equilibrium and assuming a linear equilibrium profile, we have applied the present approach and calculated the corresponding resonant continuum damping rate of TAE modes. Here, s and [alpha] denote, respectively, the strengths of magnetic shear and pressure gradients. In particular, it is found that there exists a critical [alpha][sub c](s), such that, as [alpha] [yields] [alpha][sub c], the continuum damping rate is significantly enhanced and, thus, could suppress the potential TAE instability.

• Research Organization: Princeton Univ., NJ (United States). Plasma Physics Lab.
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 7368751
• Report Number(s): PPPL-2908; ON: DE93014598
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700340* -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
ALFVEN WAVES
ASPECT RATIO
BALLOONING INSTABILITY
CALCULATION METHODS
CLOSED PLASMA DEVICES
DAMPING
DISPERSION RELATIONS
EIGENVALUES
HYDROMAGNETIC WAVES
INSTABILITY
LANDAU DAMPING
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PRESSURE GRADIENTS
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
VARIATIONAL METHODS