Mode structure and continuum damping of high-n toroidal Alfven eigenmodes

Technical Report · Sat Feb 01 04:00:00 EST 1992

OSTI ID:10133717

Rosenbluth, M N ^[1]; Berk, H L; Van Dam, J W; Lindberg, D M ^[2]

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1. California Univ., San Diego, La Jolla, CA (United States). Dept. of Physics
2. Texas Univ., Austin, TX (United States). Inst. for Fusion Studies

An asymptotic theory is described for calculating the mode structure and continuum damping of short wave-length toroidal Alfven eigenmodes (TAE). The formalism somewhat resembles the treatment used for describing low-frequency toroidal modes with singular structure at a rational surface, where an inner solution, which for the TAE mode has toroidal coupling, is matched to an outer toroidally uncoupled solution. A three-term recursion relation among coupled poloidal harmonic amplitudes is obtained, whose solution gives the structure of the global wavefunction and the complex eigenfrequency, including continuum damping. Both analytic and numerical solutions are presented. The magnitude of the damping is essential for determining the thresholds for instability driven by the spatial gradients of energetic particles (e.g., neutral beam-injected ions or fusion-product alpha particles) contained in a tokamak plasma.

• Research Organization: Texas Univ., Austin, TX (United States). Inst. for Fusion Studies
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG05-80ET53088; FG03-88ER53275
• OSTI ID: 10133717
• Report Number(s): DOE/ET/53088--537; IFSR--537; ON: DE92010547
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700330
700340
ALFVEN WAVES
ALPHA PARTICLES
FINITE DIFFERENCE METHOD
LANDAU DAMPING
PLASMA KINETICS, TRANSPORT, AND IMPURITIES
PLASMA WAVES, OSCILLATIONS, AND INSTABILITIES
TOKAMAK DEVICES
WAVE FUNCTIONS