We present a newly developed approach to solar coronal magnetic field extrapolation from vector magnetograms, based on the Principle of Minimum Dissipation Rate (MDR). The MDR system was derived from a variational problem that is more suitable for an open and externally driven system, like the solar corona. The resulting magnetic field equation is more general than force-free. Its solution can ...

Using observations from the SOHO, STEREO and Hinode, we investigate magnetic field evolution in an equatorial coronal hole region. Two dipoles emerge one by one. The negative element of the first dipole disappears due to the interaction with the positive element of the second dipole. During this process, a jet and a plasma eruption are observed. The opposite polarities of the second dipole sepa...

This is a mathematical study of the long-lived hydromagnetic structures produced in the tenuous solar corona by the turbulent, resistive relaxation of a magnetic field under the condition of extremely high electrical conductivity. The relaxation theory of Taylor (1974), originally developed for a laboratory device, is extended to treat the open atmosphere where the relaxing field must interact ...

The difficulties of constructing a three-dimensional, continuous force-free magnetic field in the solar corona are investigated through a boundary value problem posed for the unbounded domain external to a unit sphere. The normal field component Bn and the boundary value b of the twist function on the unit sphere, combined with the demand for a vanishing field at infinity, do constitute suffici...

We present a theoretical magnetohydrodynamic (MHD) model describing the time-dependent expulsion of a three-dimensional coronal mass ejection (CME) out of the solar corona. The model relates the white-light appearance of the CME to its internal magnetic Ðeld, which takes the form of a closed bubble, Ðlled with a partly anchored, twisted magnetic Ñux rope, and embedded in an otherwise open backg...

Nonlinear force-free solutions for the magnetic field in the solar corona constructed using photospheric vector magnetic field boundary data suffer from a basic problem: the observed boundary data are inconsistent with the nonlinear force-free model. Specifically, there are two possible choices of boundary conditions on vertical current provided by the data, and the two choices lead to differen...

Several unexpected astrophysical observations can be explained by gravitationally captured massive axions or axion-like particles, which are produced inside the Sun or other stars and are accumulated over cosmic times. Their radiative decay in solar outer space would give rise to a 'self-irradiation' of the whole star, providing the time-independent component of the corona heating source (we do...

We present the first theoretical, forward calculations of the Stokes profiles of several magnetic dipole (‘‘M1’’) coronal emission lines produced in current-carrying magnetic structures. An idealized coronal model of Low, Fong, and Fan is used, which describes a spherically symmetric, hydrostatic background atmosphere, isothermal at a coronal temperature of 1:6 ; 10 K. Embedded is a global, axi...

The chromosphere is the site of weak emission lines characterizing the flash spectrum observed for a few seconds during a total eclipse. This layer of the solar atmosphere is known to possess an opaque Hα emission and a great number of spicules, which can extend well above the photosphere. A stunning variety of hydrogen emission lines have been observed in this region. The production of these l...

Using polarized brightness (pB) measurements made by the High Altitude Observatory (HAO) Mauna Loa Mk III K-coronameter, we investigate the daily changes of path-integrated density at 1.15 R,. During 1996, when simultaneous pB and helioseismology data were available, we find that the correlation of pB (at zero time lag and 207 latitude lag) varies with latitude in the same way that the subsurfa...