Magnetohydrodynamic Instabilities in Shearing, Rotating, Stratified Winds and Disks

Abstract

We investigate shear and buoyancy instabilities in radially stratified, magnetized, cylindrical flows, for application to magnetocentrifugally driven winds and to magnetized accretion disks. We identify and study nine principal types of instabilities/overstabilities. When magnetic fields are predominantly toroidal, as in protostellar winds, the system exhibits axisymmetric fundamental (FM) and toroidal resonance modes, axisymmetric and non-axisymmetric toroidal buoyancy (TB) modes, and non-axisymmetric magnetorotational instability (MRI) modes. Winds with sufficiently steep field gradients are unstable to the FM, which promotes narrow dense jets in the centers of wider winds. The TB modes promote small-scale radial mixing. The MRIs have very low growth rates under low-temperature wind conditions. The stabilization of buoyancy modes by shear, and of MRIs by compressibility, may be important in allowing protostellar winds to propagate over vast distances in space. When magnetic fields are predominantly poloidal, as in winds close to their source or in astrophysical disks, the system exhibits axisymmetric Balbus-Hawley (BH), poloidal buoyancy (PB), non-axisymmetric geometric buoyancy (GPB), and poloidal resonance modes. The BH mode has the fastest growth rate. The PB mode promotes radial mixing on small scales. The GPB mode at high m is readily stabilized by shear. We extend previous MRI analyses to focus on compressibility. We introduce a ``coherent wavelet'' technique to derive closed-form expressions for instantaneous instability criteria, growth rates, and net amplification factors for non-axisymmetric MRIs in compressible flows with both poloidal and toroidal fields. We confirm that these are in excellent agreement with the results of shearing-sheet temporal integrations.

65 pages, 17 postscript figures, Accepted for publication in ApJ

References in corpus (2)

• The Formation and Structure of a Strongly Magnetized Corona above Weakly Magnetized Accretion Disks
• Bipolar molecular outflows driven by hydromagnetic protostellar winds

Cited by in corpus (63)

• Theory of Star Formation
• Angular Momentum Transport by MHD Turbulence in Accretion Disks: Gas Pressure Dependence of the Saturation Level of the Magnetorotational Instability
• Experimental observation and characterization of the magnetorotational instability
• Heat and Dust in Active Layers of Protostellar Disks
• Magnetized Accretion-Ejection Structures: 2.5D MHD simulations of continuous Ideal Jet launching from resistive accretion disks
• Convective Overstability in radially stratified accretion disks under thermal relaxation
• Accretion Discs with Strong Toroidal Magnetic Fields
• Amplification, Saturation, and Q Thresholds for Runaway: Growth of Self-Gravitating Structures in Models of Magnetized Galactic Gas Disks
• Advection of Magnetic Fields in Accretion Disks: Not So Difficult After All
• A Feature Movie of SiO Emission 20-100 AU from the Massive Young Stellar Object Orion Source I
• Three-Dimensional Simulations of Parker, Magneto-Jeans, and Swing Instabilities in Shearing Galactic Gas Disks
• Magnetorotationally-Driven Galactic Turbulence and the Formation of Giant Molecular Clouds
• Magnetized Accretion and Dead Zones in Protostellar Disks
• Dust Transport in Protostellar Disks Through Turbulence and Settling
• Radiatively inefficient MHD accretion-ejection structures
• Local Three-Dimensional Simulations of Magneto-Rotational Instability in Radiation-Dominated Accretion Disks
• The Stability of Magnetized Rotating Plasmas with Superthermal Fields
• Thermal and Magnetorotational Instability in the ISM: Two-Dimensional Numerical Simulations
• High Resolution Simulations of the Plunging Region in a Pseudo-Newtonian Potential: Dependence on Numerical Resolution and Field Topology
• Waves and Instabilities in Accretion Disks: MHD Spectroscopic Analysis
• Dead zones as safe-havens for planetesimals: influence of disc mass and external magnetic field
• Local Axisymmetric Simulations of Magneto-Rotational Instability in Radiation-Dominated Accretion Disks
• Magnetic outflows from turbulent accretion disks: I. Vertical structure & secular evolution
• A ballistic bow shock model for jet-driven protostellar outflow shells
• Cosmic Ray History and its Implications for Galactic Magnetic Fields
• Nonradial and nonpolytropic astrophysical outflows. V. Acceleration and collimation of self-similar winds
• Thermodynamics of an Accretion Disk Annulus with Comparable Radiation and Gas Pressure
• Surface Structure in an Accretion Disk Annulus with Comparable Radiation and Gas Pressure
• Herbig Stars' Near-Infrared Excess: An Origin in the Protostellar Disk's Magnetically-Supported Atmosphere
• Linear stability analysis of magnetized relativistic rotating jets
• Nonaxisymmetric Magnetorotational Instability in Proto-Neutron Stars
• Magnetic Coupling in the Disks Around Young Gas Giant Planets
• The Saturation Limit of the Magnetorotational Instability
• Local Stability of Strongly Magnetized Black Hole Tori
• Instability in strongly magnetized accretion discs: A global perspective
• Magnetorotational Instability in Electrically Driven Flow of Liquid Metal: Spectral Analysis
• Linear stability analysis of magnetized jets: the rotating case
• Magnetic field morphology and evolution in the Central Molecular Zone and its effect on gas dynamics
• The Role of the Magnetorotational Instability in the Sun
• On Hydromagnetic Stresses in Accretion Disk Boundary Layers
• Nonaxisymmetric stability in the shearing sheet approximation
• Are Magnetic Wind-Driving Disks Inherently Unstable?
• Magnetohydrodynamic Shearing Waves
• Magnetohydrodynamic Density Waves in a Composite Disk System of Interstellar Medium and Cosmic-Ray Gas
• Spiral-arm instability - II: magnetic destabilisation
• Energy partition between Alfvénic and compressive fluctuations in magnetorotational turbulence with near-azimuthal mean magnetic field
• Magnetohydrodynamics of protoplanetary discs
• Linear stability of magnetized massive protoplanetary disks
• Vertical Structure of Magnetized Accretion Disks around Young Stars
• Cross-correlation Aided Transport in Stochastically Driven Accretion Flows
• Structures in a class of magnetized scale-free discs
• Magnetohydrodynamic stability of stochastically driven accretion flows
• Thermal stability of a weakly magnetized rotating plasma
• A pure hydrodynamic instability in shear flows and its application to astrophysical accretion disks
• Parametric Survey of Nonaxisymmetric Accretion Disk Instabilities: Magnetorotational Instability to Super-Alfvénic Rotational Instability
• Angular momentum transport and thermal stabilization of optically thin, advective accretion flows through large-scale magnetic fields
• Radiation-magnetohydrodynamic Simulations of Accretion Flow Formation After a Tidal Disruption Event
• Origin of hydrodynamic instability from noise: from laboratory flow to accretion disk
• Hydrodynamical instability with noise in the Keplerian accretion discs: Modified Landau equation
• Forced linear shear flows with rotation: rotating Couette-Poiseuille flow, its stability and astrophysical implications
• Magnetorotational Instability in Diamagnetic, Misaligned Protostellar Discs
• High-growth-rate magnetohydrodynamic instability in differentially rotating compressible flow
• Instabilities in Cylindrical Geometry Using the Minimalist Approach: Formalism and Rotational Instabilities