Magnetohydrodynamic instability in differentially rotating compressible flow
نویسنده
چکیده
Transport of angular momentum is one of the thrust areas of astrophysical flows. Instabilities and hence the turbulence generated by it has been invoked to understand its role in angular momentum transport in hydrodynamic and magnetohydrodynamic regime. Investigation of an unexplored region described by the parameter space Ω e < 0, Ωe being the epicyclic frequency, resulted in a powerful magnetohydrodynamic instability. The growth rate of this instability is rather large and is found to depend on the wavenumber.
منابع مشابه
High-growth-rate magnetohydrodynamic instability in differentially rotating compressible flow.
The transport of angular momentum in the outward direction is the fundamental requirement for accretion to proceed in an accretion disk. This objective can be achieved if the accretion flow is turbulent. Instabilities are one of the sources for the turbulence. We study a differentially rotating compressive flow in the presence of nonvanishing radial and azimuthal magnetic field and demonstrate ...
متن کاملAlfvén instability in a compressible flow.
A new ideal magnetohydrodynamic instability is presented. It is shown that linear incompressible Alfvénic disturbances can get over-reflected and exponentially amplified in compressible plasma flows. A simple and transparent stability criterion for a two-layer model is derived. The instability does not require a shear in the flow and may arise for rather moderate sub-Alfvénic flow speeds. It is...
متن کاملCompressibility and local instabilities of differentially rotating magnetized gas
We study the stability of compressible cylindrical differentially rotating flow in the presence of the magnetic field, and show that compressibility alters qualitatively the stability properties of flows. Apart from the well-known magnetorotational instability that can occur even in incompressible flow, there exist a new instability caused by compressibility. The necessary condition of the newl...
متن کاملOn the relation between viscoelastic and magnetohydrodynamic flows and their instabilities
We demonstrate a close analogy between a viscoelastic medium and an electrically conducting fluid containing a magnetic field. Specifically, the dynamics of the Oldroyd-B fluid in the limit of large Deborah number corresponds to that of a magnetohydrodynamic (MHD) fluid in the limit of large magnetic Reynolds number. As a definite example of this analogy, we compare the stability properties of ...
متن کاملHydromagnetic instability in differentially rotating flows.
We study the stability of compressible differentially rotating flows in the presence of the magnetic field, and we show that the compressibility profoundly alters the previous results for a magnetized incompressible flow. The necessary condition of newly found instability can be easily satisfied in various flows in laboratory and astrophysical conditions and reads BsBphiOmega' not equal to 0, w...
متن کامل