Competition among nonlinear effects in tearing instability saturation

Journal Article · Thu Oct 01 00:00:00 EDT 1992 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860477· OSTI ID:7250449

Malara, F; Veltri, P; Carbone, V ^[1]

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1. Dipartimento di Fisica, Universita della Calabria, 87036 Roges (Italy)

The nonlinear evolution of a tearing instability in a sheet pinch in a slab geometry is numerically studied. It is found that, when the whole unstable spectrum is excited, to a small but finite level, a new nonlinear effect, an inverse energy cascade, occurs. The inverse cascade corresponds, in the physical space, to a coalescence process. The nonlinear development of the instability is then considerably modified with respect to the case in which only one unstable mode is present. In particular, the inverse cascade is responsible for the saturation of the single tearing-unstable modes. However, the nonlinear effects associated to the coalescence do not slow the growth of the instability, as a whole. On the contrary, the perturbation energy exponentially also grows during the nonlinear stage, up to the saturation of the instability. Moreover, a recurrent behavior is found after the saturation, corresponding to the creation of localized current sheets, where new tearing instabilities develop. The competition among the different nonlinear effects is discussed.

• OSTI ID: 7250449
• Journal Information: Physics of Fluids B; (United States), Vol. 4:10; ISSN 0899-8221
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
TEARING INSTABILITY
ENERGY CASCADE
SATURATION
HARMONICS
INSTABILITY GROWTH RATES
MAGNETOHYDRODYNAMICS
SLABS
TURBULENCE
FLUID MECHANICS
HYDRODYNAMICS
INSTABILITY
MECHANICS
OSCILLATIONS
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
WASTE HEAT UTILIZATION
WASTE PRODUCT UTILIZATION
700340* - Plasma Waves
Oscillations
& Instabilities- (1992-)