ON FORCE-FREE MAGNETIC FIELDS

Symmetries and solutions of equations describing force-free magnetic fields

New analytical results for two-dimensional force-free fields are presented. First, a number of exact solutions for force-free fields described by Liouville equation are given and their physical relevance for laboratory and astrophysical plasmas is discussed. Subsequently, Lie point symmetries of Liouville equation are reviewed and Lie point symmetries of the equation describing helically symmet...

Knotted linear force-free magnetic fields- topological sspects

The problem of computing linear force-free magnetic fields on a knotted multiply-connected domain is considered. The domain is the support of the current distribution, and the linear force-free fieldproblem reduces to finding an eigenfield of a self-adjoint curl operator. In this context, the GKN Theorem is reformulated in terms of symplectic geometry in order to characterize the self-adjoint e...

Spatially Periodic, Force-free Magnetic Fields with Resistive Decay*

Force-free magnetic fields, i.e. fields that are either parallel or antiparallel to the electric current, occur in the solar chromosphere and also have been used in certain magnetic confinement schemes in controlled thermonuclear fusion research. In this paper, we derive a general expression for force-free fields that decay resistively and are spatially periodic. The general expression that is ...

Reconstruction of Solar Coronal Linear Force-Free Magnetic Field

Effect of Polarimetric Noise on the Estimation of Twist and Magnetic Energy of Force-Free Fields

The force-free parameter α, also known as helicity parameter or twist parameter, bears the same sign as the magnetic helicity under some restrictive conditions. The single global value of α for a whole active region gives the degree of twist per unit axial length. We investigate the effect of polarimetric noise on the calculation of global α value and magnetic energy of an analytical bipole. Th...