We consider the stability of a configuration consisting of a vertical magnetic field in a planar flow on elliptical streamlines in ideal hydromagnetics. In the absence of a magnetic field the elliptical flow is universally unstable (the “elliptical instability”). We find this universal instability persists in the presence of magnetic fields of arbitrary strength, although the growthrate decreas...

Scientists aspire to understand the underlying physics behind the formation of instabilities in soft matter and how to manipulate them for diverse investigations, while engineers aim to design materials that inhibit or impede the nucleation and growth of these instabilities in critical applications. The present paper reviews the field-induced rotational instabilities which may occur in chiral s...

The development of instabilities in soft heterogeneous dielectric elastomers is investigated. Motivated by experiments and possible applications, we use in our analysis the physically relevant referential electric field instead of electric displacement. In terms of this variable, a closed form solution is derived for the class of layered neo-Hookean dielectrics. A criterion for the onset of ele...

Shear instabilities were investigated in an exchange flow in a tilting channel. The channel is connected to a freshwater reservoir at one end and a salt water reservoir at the other end. When the channel is initially horizontal, a steady two-layer flow occurs that supports symmetric Holmboe instabilities. When the channel is tilted, as in closed tilting channel experiments, shear increases and ...

Radiative cooling by metals in shocked gas mediates the formation of ionization front instabilities in the galaxy today that are responsible for a variety of phenomena in the interstellar medium, from the morphologies of nebulae to triggered star formation in molecular clouds. An important question in early reionization and chemical enrichment of the intergalactic medium is whether such instabi...

The beta limit by the ideal MHD instabilities (so-called “MHD stability beta limit”) for helical plasmas is studied by a hierarchy integrated simulation code. A numerical model for the effect of the MHD instabilities is introduced such that the pressure profile is flattened around the rational surface due to the MHD instabilities. The width of the flattening of the pressure gradient is determin...

Energetic nonthermal particles (cosmic rays, CRs) are accelerated in supernova remnants, relativistic jets and other astrophysical objects. The CR energy density is typically comparable with that of the thermal components and magnetic fields. In this review we discuss mechanisms of magnetic field amplification due to instabilities induced by CRs. We derive CR kinetic and magnetohydrodynamic equ...