Related papers: Relationship between photospheric currents and cor…
The emergence of dipolar magnetic features on the solar surface is an idealization. Most of the magnetic flux emergence occurs in complex multipolar regions. Here, we show that the surface pattern of magnetic structures alone can reveal the…
Solar flares and coronal mass ejections are the largest energy release phenomena in the current solar system. They cause drastic enhancements of electromagnetic waves of various wavelengths and sometimes eject coronal material into the…
Observation of solar-like stars show a clear relation between X-ray emission and their rotation. Higher stellar rotation can lead to a larger magnetic helicity production in stars. We aim to understand the relation between magnetic helicity…
Understanding the nature and evolution of the photospheric helicity flux transfer is a key to reveal the role of magnetic helicity in coronal dynamics of solar active regions. Using SDO/HMI photospheric vector magnetograms and the derived…
Magnetic helicity is a physical quantity that describes field topology. It is also a conserved quantity as Berger in 1984 demonstrated that the total magnetic helicity is still conserved in the corona even when there is a fast magnetic…
We compare the coronal magnetic energy and helicity of two solar active regions (ARs), prolific in major eruptive (AR~11158) and confined (AR~12192) flaring, and analyze the potential of deduced proxies to forecast upcoming flares. Based on…
An investigation on correlations between photospheric current helicity and subsur- face kinetic helicity is carried out by analyzing vector magnetograms and subsurface velocities for two rapidly developing active regions. The vector…
To study the three-dimensional (3D) magnetic field topology and its long-term evolution associated with the X3.4 flare of 2006 December 13, we investigate the coronal relative magnetic helicity in the flaring active region (AR) NOAA 10930…
Using a recently proposed nonlinear force-free method designed for single vector magnetograms of solar active regions we calculate the instantaneous free magnetic energy and relative magnetic helicity budgets in 162 vector magnetograms…
In this paper we continue our theoretical studies on addressing what are the possible consequences of magnetic helicity accumulation in the solar corona. Our previous studies suggest that coronal mass ejections (CMEs) are natural products…
Magnetic helicity flux gives information about the topology of a magnetic field passing through a boundary. In solar physics applications, this boundary is the photosphere and magnetic helicity flux has become an important quantity in…
Magnetic helicity is an important concept in solar physics, with a number of theoretical statements pointing out the important role of magnetic helicity in solar flares and coronal mass ejections (CMEs). Here we construct a sample of 47…
We study the magnetic field and current structure associated with a coronal loop. Through this we investigate to what extent the assumptions of a force-free magnetic field break down and where they might be justified. We analyse a 3D MHD…
Helicity measures complexity in the field. Magnetic helicity is given by a volume integral over the scalar product of magnetic field {\bf B} and its vector potential {\bf A}. A direct computation of magnetic helicity in the solar atmosphere…
Observations of magnetic helicity transportation through the solar photosphere reflect the interaction of turbulent plasma movements and magnetic fields in the solar dynamo process. In this chapter, we have reviewed the research process of…
A loss of magnetic field confinement is believed to be the cause of coronal mass ejections (CMEs), a major form of solar activity in the corona. The mechanisms for magnetic energy storage are crucial in understanding how a field may possess…
Potential field extrapolations are widely used as minimum-energy models for the Sun's coronal magnetic field. As the reference to which other magnetic fields are compared, they have -- by any reasonable definition -- no global (signed)…
The electric current helicity density $\displaystyle \chi=\langle\epsilon_{ijk}b_i\frac{\partial b_k}{\partial x_j}\rangle$ contains six terms, where $b_i$ are components of the magnetic field. Due to the observational limitations, only…
Relative magnetic helicity is a gauge invariant quantity suitable for the study of the magnetic helicity content of heliospheric plasmas. Relative magnetic helicity can be decomposed uniquely into two gauge invariant quantities, the…
We self-consistently derive the magnetic energy and relative magnetic helicity budgets of a three-dimensional linear force-free magnetic structure rooted in a lower boundary plane. For the potential magnetic energy we derive a general…