An integrated Magneto-Fluid model, that accords full treatment to the Velocity fields associated with the directed plasma motion, is developed to investigate the dynamics of coronal structures. It is suggested that the interaction of the fluid and the magnetic aspects of plasma may be a crucial element in creating so much diversity in the solar atmosphere. It is shown that the structures which comprise the solar corona can be created by particle (plasma) flows observed near the Sun's surface -the primary heating of these structures is caused by the viscous dissipation of the flow kinetic energy.

By modelling the coronal structures by "slowly" evolving Double-Beltrami two-fluid equilibria (created by the interaction of the magnetic and velocity fields), the conditions for catastrophic transformations of the original state are derived. It is shown that, at the transition, much of the magnetic energy of the original state is converted to the the flow kinetic energy.

By modeling the closed field structures in the solar atmosphere by '' slowly '' evolving double Beltrami twofluid equilibria (created by the interaction of the magnetic and velocity fields), the conditions for catastrophic transformations of the original state are derived. The analysis for predicting sudden changes is carried out through a set of algebraic equations obtained by relating the four characteristic parameters (two eigenvalues and two amplitudes) of the equilibrium to the macroscopic constants of motion (helicities and energy). It is shown that a catastrophic loss of equilibrium occurs when the macro scale of a closed structure, interacting with its local surroundings, decreases below a critical value; the catastrophe is possible only if the total energy of the structure (for given helicities) also exceeds a well-defined threshold. It is further shown that at the transition much of the magnetic energy of the original state is converted to the flow kinetic energy.

A new class of Double Beltrami-Bernoulli equilibria, sustained by electron degeneracy pressure, are investigated. It is shown that due to electron degeneracy, a nontrivial Beltrami-Bernoulli equilibrium state is possible even for a zero temperature plasma. These states are, conceptually, studied to show the existence of new energy transformation pathways converting, for instance, the degeneracy energy into fluid kinetic energy. Such states may be of relevance to compact astrophysical objects like white dwarfs, neutron stars etc.

The "reverse-dynamo" mechanism - the amplification/generation of fast plasma flows by micro scale (turbulent) magnetic fields via magneto-fluid coupling is recognized and explored. It is shown that macro-scale magnetic fields and flows are generated simultaneously and proportionately from micro scale fields and flows. The stronger the micro-scale driver, the stronger are the macro-scale products. Stellar and astrophysical applications are suggested.Comment: 16 pages including 3 figures. The Astrophys. J. (accepted); additional material is given for clarification; terminology is change

A general solenoidal vector field, such as a magnetic field or an incompressible flow, can be decomposed into an orthogonal sum of Beltrami fields (eigenfunctions of the curl operator). Nonlinear dynamics of a plasma induces complex couplings among these Beltrami fields. In a single-fluid magnetohydrodynamic (MHD) plasma, however, the energy condensates into a single Beltrami magnetic field resulting in the self-organization of a force-free equilibrium, that is, the Taylor relaxed state. By relating the velocity and the magnetic fields, the Hall term in the two-fluid model leads to a singular perturbation that enables the formation of an equilibrium given by a pair of two different Beltrami fields. This new set of relaxed states, despite the simple mathematical structure, includes a variety of plasma states that could explain a host of interesting phenomena. The H-mode (high-confinement) boundary layer, where a diamagnetic structure is self-organized under the coupling of the magnetic field, flow, electric field, and pressure, is an example. The theory also predicts the possibility of producing high beta equilibrium.

Within the framework of a two-fluid description possible pathways for the generation of fast flows (dynamical as well as steady) in the lower solar atmosphere is established. It is shown that a primary plasma flow (locally sub-Alfvénic) is accelerated when interacting with emerging/ambient arcade-like closed field structures. The acceleration implies a conversion of thermal and field energies to kinetic energy of the flow. The time-scale for creating reasonably fast flows ( 100 km/s) is dictated by the initial ion skin depth while the amplification of the flow depends on local β. It is shown, for the first time, that distances over which the flows become "fast" are ∼ 0.01 R s from the interaction surface; later the fast flow localizes (with dimensions 0.05 R S ) in the upper central region of the original arcade. For fixed initial temperature the final speed ( 500 km/s) of the accelerated flow, and the modification of the field structure are independent of the time-duration (life-time) of the initial flow. In the presence of dissipation, these flows are likely to play a fundamental role in the heating of the finely structured Solar atmosphere.

The existence of soliton-like electromagnetic (EM) distributions in a fully degenerate electronpositron plasma is studied applying relativistic hydrodynamic and Maxwell equations. For circularly polarized wave it is found that the soliton solutions exist both in relativistic as well as nonrelativistic degenerate plasmas. Plasma density in the region of soliton pulse localization is reduced considerably. The possibility of plasma cavitation is also shown.