Nonlinear dynamics of field maintenance and quasiperiodic relaxation in reversed-field pinches

Journal Article · Fri Mar 01 04:00:00 EST 1991 · Physics of Fluids B; (USA)

DOI:https://doi.org/10.1063/1.859868· OSTI ID:5711007

Ho, Y L; Craddock, G G ^[1]

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1. Science Applications International Corporation, San Diego, California 92121 (US)

The detailed dynamics underlying the self-generation of magnetic flux ( dynamo'') in reversed-field pinches (RFPs) is investigated with a three-dimensional magnetohydrodynamic code. A novel energy diagnostic is used to identify the path taken in Fourier space by the poloidal magnetic field energy as it is converted to axial magnetic field energy by the dynamo. At high values of the pinch parameter, {Theta}, and Lundquist number, {ital S}, the dynamo can be alternatingly dominated by quasilinear and nonlinear processes in a quasiperiodic fashion. Quasilinearly, the {ital m}=1 modes can reverse the axial field by themselves. However, {ital m}=0 modes are crucial to produce the nonlinear dynamo that triggers quasiperiodic relaxations. The same causal mechanism is likely to be responsible for the experimentally observed sawteeth.

• DOE Contract Number: AC03-83ER53150
• OSTI ID: 5711007
• Journal Information: Physics of Fluids B; (USA), Journal Name: Physics of Fluids B; (USA) Vol. 3:3; ISSN PFBPE; ISSN 0899-8221
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700101* -- Fusion Energy-- Plasma Research-- Confinement
Heating
& Production
FLUCTUATIONS
FLUID MECHANICS
HYDRODYNAMICS
MAGNETIC FLUX
MAGNETOHYDRODYNAMICS
MECHANICS
NONLINEAR PROBLEMS
NUMERICAL SOLUTION
OSCILLATIONS
PINCH EFFECT
PLASMA
RELAXATION
REVERSE-FIELD PINCH
SAWTOOTH OSCILLATIONS
SIMULATION
THREE-DIMENSIONAL CALCULATIONS
VARIATIONS