86 citations · 549 across the 22 of their papers we have counts for
19 papers · 1 filter
Diagnostic of Spectral Lines in Magnetized Solar Atmosphere: Formation of the H\b{eta} Line in Sunspots
Hongqi Zhang
Formation of the H 4861.34 Å line is an important topic related to the diagnosis of the basic configuration of magnetic fields in the solar and stellar chromospheres. Specifi…
Multi-wavelength Observation of a Failed Eruption from a Helical Kink-unstable Prominence
Haiqing Xu, Jiangtao Su, Jie Chen +7
Multi-wavelength observations of prominence eruptions provide an opportunity to uncover the physical mechanism of the triggering and the evolution process of the eruption. In this…
The origin and effect of hemispheric helicity imbalance in solar dynamo
S. Yang, V. V. Pipin, D. D. Sokoloff +2
In this paper we study the effects of hemispheric imbalance of magnetic helicity density on breaking the equatorial reflection symmetry of the dynamo generated large-scale magnetic…
From Polarimetry to Helicity: Studies of Solar Magnetic Fields at the Huairou Solar Observing Station
Hongqi Zhang
In this paper, we briefly introduce the basic questions in the measurements of solar magnetic fields and the possible error sources due to the approximation of the theory of radiat…
Improvements of the Longitudinal Magnetic Field Measurement from the Solar Magnetic Field Telescope at Huairou Solar Observing Station
Andrei Plotnikov, Alexander Kutsenko, Shanbin Yang +4
The weak-field approximation implying linear relationship between Stokes and longitudinal magnetic field, , often suffers from saturation observed in strong magnet…
Solar Kinetic Energy and Cross Helicity Spectra
Hongqi Zhang, Axel Brandenburg
We develop a formalism that treats the calculation of solar kinetic energy and cross helicity spectra in an equal manner to that of magnetic energy and helicity spectra. The magnet…
Intermittency spectra of current helicity in solar active regions
A. S. Kutsenko, V. I. Abramenko, K. M. Kuzanyan +2
We analyse the spatial distribution of current helicity in solar active regions. A comparison of current helicity maps derived from three different instruments (Helioseismic and Ma…
Evolution of Relative Magnetic Helicity: New Boundary Conditions for the Vector Potential
Shangbin Yang, Joerg Buechner, Jan Skala +1
We recently proposed a method to calculate the relative magnetic helicity in a finite volume for a given magnetic field which however required the flux to be balanced separately on…
Photospheric Magnetic Free Energy Density of Solar Active Regions
Hongqi Zhang
We present the photospheric energy density of magnetic fields in two solar active regions inferred from observational vector magnetograms, and compare it with the possible differen…
Evolution of Magnetic Helicity and Energy Spectra of Solar Active Regions
Hongqi Zhang, Axel Brandenburg, D. D. Sokoloff
We adopt an isotropic representation of the Fourier-transformed two-point correlation tensor of the magnetic field to estimate the magnetic energy and helicity spectra as well as c…
A solar eruption driven by rapid sunspot rotation
Guiping Ruan, Yao Chen, Shuo Wang +8
We present the observation of a major solar eruption that is associated with fast sunspot rotation. The event includes a sigmoidal filament eruption, a coronal mass ejection, and a…
Magnetic helicity and energy spectra of a solar active region
Hongqi Zhang, Axel Brandenburg, D. D. Sokoloff
We compute for the first time magnetic helicity and energy spectra of the solar active region NOAA 11158 during 11-15 February 2011 at 20^o southern heliographic latitude using obs…
Magnetic Nonpotentiality in Photospheric Active Regions as a Predictor of Solar Flares
Xiao Yang, GangHua Lin, HongQi Zhang +1
Based on several magnetic nonpotentiality parameters obtained from the vector photospheric active region magnetograms obtained with the Solar Magnetic Field Telescope at the Huairo…
Method of Relative Magnetic Helicity Computation II: Boundary Conditions for the Vector Potentials
Shangbin Yang, Jörg Büchner, Jean Carlo Santos +1
We have proposed a method to calculate the relative magnetic helicity in a finite volume as given the magnetic field in the former paper (Yang et al. {\it Solar Physics}, {\bf 283}…
Analysis on Correlations between Subsurface Kinetic Helicity and Photospheric Current Helicity in Active Regions
Yu Gao, Junwei Zhao, Hongqi Zhang
An investigation on correlations between photospheric current helicity and subsur- face kinetic helicity is carried out by analyzing vector magnetograms and subsurface velocities f…
A Statistical Study on Force-Freeness of Solar Magnetic Fields in the Photosphere
S. Liu, J. T. Su, H. Q. Zhang +4
It is an indisputable fact that solar magnetic fields are force-free in the corona, where force free fields means that current and magnetic fields are parallel and there is no Lore…
A Statistical Study on Photospheric Magnetic Nonpotentiality of Active Regions and Its Relationship with Flares during Solar Cycles 22-23
Xiao Yang, HongQi Zhang, Yu Gao +2
A statistical study is carried out on the photospheric magnetic nonpotentiality in solar active regions and its relationship with associated flares. We select 2173 photospheric vec…
Large Scale Soft X-ray Loops And Their Magnetic Chirality In Both Hemispheres
Hongqi Zhang, Shangbin Yang, Yu Gao +3
The magnetic chirality in solar atmosphere has been studied based on the soft X-ray and magnetic field observations. It is found that some of large-scale twisted soft X-ray loop sy…
New dynamo pattern revealed by solar helical magnetic fields
Hongqi Zhang, T. Sakurai, A. Pevtsov +4
Previously unobservable mirror asymmetry of the solar magnetic field -- a key ingredient of the dynamo mechanism which is believed to drive the 11-year activity cycle -- has now be…