Limits on m = 2, n = 1 error field induced locked mode instability in TPX with typical sources of poloidal field coil error field and a prototype correction coil, C-coil''

Technical Report · Tue Dec 01 00:00:00 EST 1992

DOI:https://doi.org/10.2172/6274164· OSTI ID:6274164

La Haye, R J

Irregularities in the winding or alignment of poloidal or toroidal magnetic field coils in tokamaks produce resonant low m, n = 1 static error fields. Otherwise stable discharges can become nonlinearly unstable, and locked modes can occur with subsequent disruption when subjected to modest m = 2, n = 1 external perturbations. Using both theory and the results of error field/locked mode experiments on DIII-D and other tokamaks, the critical m = 2, n = 1 applied error field for locked mode instability in TPX is calculated for discharges with ohmic, neutral beam, or rf heating. Ohmic discharges axe predicted to be most sensitive, but even co-injected neutral beam discharges (at [beta][sub N] = 3) in TPX will require keeping the relative 2, 1 error field (B[sub r21]/B[sub T]) below 2 [times] 10[sup [minus]4]. The error fields resulting from as-built'' alignment irregularities of various poloidal field coils are computed. Coils if well-designed must be positioned to within 3 mm with respect to the toroidal field to keep the total 2,1 error field within limits. Failing this, a set of prototype correction coils is analyzed for use in bringing 2,1 error field down to a tolerable level.

• Research Organization: General Atomics, San Diego, CA (United States)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-89ER51114
• OSTI ID: 6274164
• Report Number(s): GA-A-21167; ON: DE93014408
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
MAGNETIC FIELDS
ERRORS
TOKAMAK DEVICES
PLASMA INSTABILITY
ALIGNMENT
BEAM INJECTION HEATING
CONFINEMENT TIME
POLOIDAL FIELD DIVERTORS
RF SYSTEMS
CLOSED PLASMA DEVICES
DIVERTORS
HEATING
INSTABILITY
PLASMA HEATING
THERMONUCLEAR DEVICES
700430* - Fusion Technology- Magnet Coils & Fields- (1992-)
700340 - Plasma Waves
Oscillations
& Instabilities- (1992-)