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Energy of Force-Free Magnetic Fields in Relation to Coronal Mass Ejections

Description: In typical observations of coronal mass ejections (CMEs), a magnetic structure of a helmet-shaped closed configuration bulges out and eventually opens up. However, a spontaneous transition between these field configurations has been regarded to be energetically impossible in force-free fields according to the Aly-Sturrock theorem. The theorem states that the maximum energy state of force-free fields with a given boundary normal field distribution is the open field. The theorem implicitly assumes the existence of the maximum energy state, which may not be taken for granted. In this study, we have constructed force-free fields containing tangential discontinuities in multiple flux systems. These force-free fields can be generated from a potential field by footpoint motions that do not conserve the boundary normal field distribution. Some of these force-free fields are found to have more magnetic energy than the corresponding open fields. The constructed force-free configurations are compared with observational features of CME-bearing active regions. Possible mechanisms of CMEs are also discussed.
Date: May 9, 2002
Creator: Choe, G.S. & Cheng, C.Z.
Partner: UNT Libraries Government Documents Department

The origin of all cosmic rays : a space-filling mechanism.

Description: There is a need for one mechanism to accelerate cosmic rays universally over the full energy spectrum, isotropically, and space filling. The current view is a theory based upon a series of mechanisms, patched to fit various spectral regions with a mechanism for the origin of the UHCRs still in doubt. We suggest that the reconnection of force-free magnetic fields produced by the twisting of all imbedded magnetic flux by the vorticity motion of all accretion or condensations both within the Galaxy as well as the metagalaxy is the universal mechanism. This leads to the acceleration of all cosmic rays with both total energy and individual energies up to the highest observed of 3 x 10{sup 20} ev and predicting an upper limit of 10{sup 23} ev. There are three primary, and we believe compelling reasons for adopting this different view of the origin of CRs. (1) The energy source is space filling and isotropic, thereby avoiding any anisotropy's due to single sources, e.g., supernovae remnants and AGN. (2) The galactic and particularly the extragalactic energy source is sufficient to supply the full energy of a universal galactic and extragalactic spectrum of 10{sup 60} to 10{sup 61} ergs sufficient to avoid the GZK cut-off. (3) Efficient E{sub parallel} acceleration from reconnection of force-free fields is well observed in the laboratory whereas collisionless shock acceleration still eludes laboratory confirmation.
Date: January 1, 2001
Creator: Colgate, S. A. (Stirling A.) & Li, H. (Hui)
Partner: UNT Libraries Government Documents Department

THE ORIGIN OF ALL COSMIC RAYS: A SPACE-FILLING MECHANISM

Description: There is a need for one mechanism to accelerate cosmic rays universally over the full energy spectrum, isotropically, and space filling. The current view is a theory based upon a series of mechanisms, patched to fit various spectral regions with a mechanism for the origin of the UHCRs still in doubt. We suggest that the reconnection of force-free magnetic fields produced by the twisting of all imbedded magnetic flux by the vorticity motion of all accretion or condensations both within the Galaxy as well as the metagalaxy is the universal mechanism. This leads to the acceleration of all cosmic rays with both total energy and individual energies up to the highest observed of 3 x 10{sup 20} ev and predicting an upper limit of 10{sup 23} ev. There are three primary, and we believe compelling reasons for adopting this different view of the origin of CRs. (1) The energy source is space filling and isotropic, thereby avoiding any anisotropy's due to single sources, e.g., supernovae remnants and AGN. (2) The galactic and particularly the extragalactic energy source is sufficient to supply the full energy of a universal galactic and extragalactic spectrum of 10{sup 60} to 10{sup 61} ergs sufficient to avoid the GZK cut-off. (3) Efficient E{sub parallel} acceleration from reconnection of force-free fields is well observed in the laboratory whereas collisionless shock acceleration still eludes laboratory confirmation.
Date: March 1, 2001
Creator: COLGATE, S. & LI, H.
Partner: UNT Libraries Government Documents Department

A Hypothesis of the Magnetostatic Turbulence and its Implications for Astrophysics

Description: Arguments are presented in favor of a possible existence of a random, force-free magnetic field. Ponderomotive forces in such a field are small, and the evolutionary time is much longer than Alfven crossing time over the vortex scale, whence the suggested term ''magnetostatic''. The presence of this long-lived random magnetic field provides stiffness with respect to large-scale compressional motions. On the other hand, such a field cannot be detected by techniques involving line-of-sight averaging. It may therefore be a source of stiffness for various astrophysical objects, ranging from plasmas in clusters of galaxies to the interiors of molecular clouds in HII regions, and remaining at the same time undetectable. Analysis of large-scale motions on the background of the magnetostatic turbulence is presented; it is concluded that these large-scale motions can be roughly described by a usual hydrodynamics for the matter with an isotropic pressure; the adiabatic index is 4/3.
Date: February 26, 2007
Creator: Ryutov, D D & Remington, B A
Partner: UNT Libraries Government Documents Department

Dynamo dominated accretion and energy flow: The mechanism of active galactic nuclei

Description: An explanation of the magnetic fields of the universe, the central mass concentration of galaxies, the massive black hole of every galaxy, and the AGN phenomena has been an elusive goal. The authors suggest here the outlines of such a theoretical understanding and point out where the physical understanding is missing. They believe there is an imperative to the sequence of mass flow and hence energy flow in the collapse of a galactic mass starting from the first non-linearity appearing in structure formation following decoupling. This first non-linearity of a two to one density fluctuation, the Lyman-{alpha} clouds, ultimately leads to the emission spectra of the phenomenon of AGN, quasars, blazars, etc. The over-arching physical principle is the various mechanisms for the transport of angular momentum. They believe they have now understood the new physics of two of these mechanisms that have previously been illusive and as a consequence they impose strong constraints on the initial conditions of the mechanisms for the subsequent emission of the gravitational binding energy. The new phenomena described are: (1) the Rossby vortex mechanism of the accretion disk {alpha}-viscosity, and (2) the mechanism of the {alpha}-{Omega} dynamo in the accretion disk. The Rossby vortex mechanism leads to a prediction of the black hole mass and rate of energy release and the {alpha}-{Omega} dynamo leads to the generation of the magnetic flux of the galaxy (and the far greater magnetic flux of clusters) and separately explains the primary flux of energy emission as force-free magnetic energy density. This magnetic flux and magnetic energy density separately are the necessary consequence of the saturation of a dynamo created by the accretion disk with a gain greater than unity.
Date: December 31, 1998
Creator: Colgate, S.A. & Li, H.
Partner: UNT Libraries Government Documents Department

Current Density and Plasma Displacement Near Perturbed Rational Surface

Description: The current density in the vicinity of a rational surface of a force-free magnetic field subjected to an ideal perturbation is shown to be the sum of both a smooth and a delta-function distribution, which give comparable currents. The maximum perturbation to the smooth current density is comparable to a typical equilibrium current density and the width of the layer in which the current flows is shown to be proportional to the perturbation amplitude. In the standard linearized theory, the plasma displacement has an unphysical jump across the rational surface, but the full theory gives a continuous displacement.
Date: October 10, 2010
Creator: Boozer, A. H. & Pomphrey, N.
Partner: UNT Libraries Government Documents Department

The galactic dynamo, the helical force free field and the emissions of AGN

Description: We present a theory relating the central galactic black hole (BH) formation to the galactic dynamo through an accretion disk. The associated AGN emissions and the collimated radio sources are then a result of the dynamo process. A unified theory of quasar and BL-Lac formation (hereafter AGN) starts with the collapse of damped Lyman-alpha clouds, presumably proto-galaxies, which then evolve to a central disk and black hole, (BH). An alpha - omega dynamo forms in this accretion disk where the augmentation of the poloidal field from the toroidal field depends upon star disk collisions. The winding number of the inner most orbit of the disk is so large, tilde 10 to the 11th power that the total gain of the dynamo is semi-infinite, and the original seed field of no consequence. The total magnetic flux produced is tilde 10000 times that of the galaxy, sufficient to explain the much larger flux of clusters. The semi-infinite gain of the dynamo implies that the field saturates at the dynamic stress so that most of the free energy of formation of the BH is carried off as magnetic energy in the form of a magnetic helix. The dissipation of this magnetic energy leads to the unique emission spectrum of AGN as well as the equally startling collimated radio and optical sources.
Date: May 1, 1997
Creator: Colgate, S. & Li, Hui
Partner: UNT Libraries Government Documents Department