Curvature-driven instabilities in the Elmo Bumpy Torus (EBT)

Conference · Fri Jan 01 04:00:00 EST 1982

OSTI ID:6814297

Abe, H; Spong, D A; Antonsen, Jr, T M; Tsang, K T; Nguyen, K T

Curvature-driven instabilities are analyzed for an EBT configuration which consists of plasma interacting with a hot electron ring whose drift frequencies are larger than the growth rates predicted from conventional magnetohydrodynamic (MHD) theory. Stability criteria are obtained for five possible modes: the conventional hot electron interchange, a high-frequency hot electron interchange (at frequencies greater than the ion-cyclotron frequency), a compressional instability, a background plasma interchange, and an interacting pressure-driven interchange. A wide parameter regime for stable operation is found, which, however, severely deteriorates for a band of intermediate mode numbers. Finite Larmor radius effects can eliminate this deterioration; moreover, all short-wavelength curvature-driven modes are stabilized if the hot electron Larmor radius rho/sub h/ satisfies (kappa/sub perpendicular/rho/sub h/)/sup 2/ > 2..delta../(R..beta../sub h/(1 + P'/sub parallel//P'/sub perpendicular/)), where kappa/sub perpendicular/ is the transverse wavenumber, ..delta.. is the ring half-width, R is the mid-plane radius of curvature, ..beta../sub h/ is the hot electron beta value, and P' is the pressure gradient. Resonant wave-particle instabilities predicted by a new low frequency variational principle show that a variety of remnant instabilities may still persist.

• Research Organization: Texas Univ., Austin (USA). Inst. for Fusion Studies; Oak Ridge National Lab., TN (USA); Maryland Univ., College Park (USA). Dept. of Physics and Astronomy; Science Applications, Inc., Boulder, CO (USA). Plasma Research Inst.; Michigan Univ., Ann Arbor (USA). Dept. of Nuclear Engineering
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6814297
• Report Number(s): CONF-820930-16; ON: DE82022334
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107* -- Fusion Energy-- Plasma Research-- Instabilities
BETA RATIO
ELMO BUMPY TORUS
ELMO DEVICES
INSTABILITY
INSTABILITY GROWTH RATES
LARMOR RADIUS
MAGNETIC MIRRORS
OPEN PLASMA DEVICES
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
THERMONUCLEAR DEVICES