搜索结果: 1-15 共查到“天体物理学 Instability”相关记录17条 . 查询时间(0.042 秒)
Large-scale magnetic field generation via the Kelvin-Helmholtz instability
Large-scale magnetic field generation Kelvin-Helmholtz instability
2011/10/18
We present the first self-consistent three-dimensional particle-in-cell simulations of the Kelvin-Helmholtz instability (KHI) in an unmagnetized scenario. We discuss the main features, including densi...
Properties of the negative effective magnetic pressure instability
magnetohydrodynamics (MHD) – instabilities – turbulence
2011/10/9
As was demonstrated in earlier studies, turbulence can result in a negative contribution to the effective mean magnetic pressure, which, in turn, can cause a large-scale instability. In this study, hy...
Giant Planet Formation by Disk Instability in Low Mass Disks?
Giant Planet Formation Disk Instability Low Mass Disks
2011/1/11
Forming giant planets by disk instability requires a gaseous disk that is massive enough to become gravitationally unstable and able to cool fast enough for self-gravitating clumps to form and survive...
Revisiting the Flowers-Ruderman instability of magnetic stars
magnetic fields MHD – stars magnetic field
2010/11/10
In 1977, Flowers and Ruderman described a perturbation that destabilises a purely
dipolar magnetic field in a fluid star. They considered the effect of cutting the star
in half along a plane contain...
Magnetic fields of Ap stars as a result of an instability
Stars chemically peculiar magnetic fields – instabilities
2010/11/15
Ap star magnetism is often attributed to fossil magnetic fields which have not changed much since the pre-main-sequence epoch of the stars. Stable magnetic field configurations are known which could p...
MHD Simulations of Parker Instability Undergoing Cosmic-Ray Diffusion: Effect of the Initial Equilibrium Conditions on Mixing
cosmic rays magnetohydrodynamics instability numerical simulation
2010/11/9
Parker instability arises from the presence of magnetic fields in a plasma such as the interstellar medium (ISM),wherein the magnetic buoyant pressure expels the gas and causes the gas to move along t...
Alpha effect due to buoyancy instability of a magnetic layer
magnetohydrodynamics Sun: magnetic fields Instabilities Turbulence Sun dynamo
2010/11/11
Context. A strong toroidal field can exist in form of a magnetic layer in the overshoot region below the solar convection zone. This motivates a more detailed study of the magnetic buoyancy instabilit...
The baroclinic instability in the context of layered accretion. Self-sustained vortices and their magnetic stability in local compressible unstratified models of protoplanetary disks
baroclinic instability magnetic stability protoplanetary disks
2010/11/10
Context. Turbulence and angular momentum transport in accretion disks remain a topic of debate. With the realization that dead zones are robust features of protoplanetary disks, the search for hydrody...
The Early Evolution of Primordial Pair-Instability Supernovae
Primordial Pair-Instability Supernovae
2011/1/10
The observational signatures of the first cosmic explosions and their chemical imprint on second-generation stars both crucially depend on how heavy elements mix within the star at the earliest stages...
Cosmic-ray current driven turbulence in shocks with efficient particle acceleration: the oblique, long-wavelength mode instability
High Energy Astrophysical Phenomena (astro-ph.HE) Plasma Physics (physics.plasm-ph)
2010/12/23
In order for diffusive shock acceleration (DSA) to accelerate particles to high energies, the energetic particles must be able to interact with magnetic turbulence over a broad wavelength range.
Forming Planetesimals by Gravitational Instability: II. How Dust Settles to its Marginally Stable State
Earth and Planetary Astrophysics (astro-ph.EP)
2010/12/23
Dust at the midplane of a circumstellar disk can become gravitationally unstable and fragment into planetesimals if the local dust-to-gas density ratio mu is sufficiently high. We simulate how dust se...
Forming Planetesimals by Gravitational Instability: I. The Role of the Richardson Number in Triggering the Kelvin-Helmholtz Instability
Earth and Planetary Astrophysics (astro-ph.EP)
2010/12/23
Gravitational instability (GI) of a dust-rich layer at the midplane of a gaseous circumstellar disk is one proposed mechanism to form planetesimals, the building blocks of rocky planets and gas giant ...
Analysis of beam plasma instability effects on incoherent scatter spectra
Ionosphere plasma
2017/3/22
Naturally Enhanced Ion Acoustic Lines (NEIALs)
detected with Incoherent Scatter Radars (ISRs) can be produced
by a Langmuir decay mechanism, triggered by a bump
on tail instability. A recent model ...
Evaluating the Magnetorotational Instability's Dependence on Numerical Algorithms and Resolution
turbulence MHD methods numerical accretion discs instabilities
2010/3/9
We have studied saturated, MRI-driven turbulence using three-dimensional, isothermal simulations with resolutions that extend from 64 to 192 zones in each direction. The simulations were performed wit...
On the Shear Instability in Relativistic Neutron Stars
Relativistic Neutron Stars Shear Instability
2010/3/18
We present new results on instabilities in rapidly and differentially rotating neutron stars. We model the stars in full general relativity and describe the stellar matter adopting a cold realistic eq...