Related papers: Helicity at Photospheric and Chromospheric Heights
In this paper we discuss the sign of helicity in the $\alpha$-$\Omega$ dynamo and propose a wave-$\Omega$ model in which the $\alpha$ effect in the geodynamo is induced by helical wave but not helical flow as in the solar dynamo. We then…
To elucidate the cascade direction of the solar wind turbulence, we analyzed magnetic helicity density spectra from the Parker Solar Probe data across more than 500 heliocentric distances. For the first time, we confirmed a persistent…
We investigate the orientation of the photospheric magnetic fields in the solar polar region using observations from the Helioseismic and Magnetic Imager (HMI). Inside small patches of significant polarization, the inferred magnetic field…
Magnetic helicity is a fundamental constraint in both ideal and resistive magnetohydrodynamics. Measurements of magnetic helicity density on the Sun and other stars are used to interpret the internal behaviour of the dynamo generating the…
The two-state solar wind paradigm is based on observations showing that slow and fast solar wind have distinct properties like helium abundances, kinetic signatures, elemental composition, and charge-state ratios. Nominally, the fast wind…
The global rotational profile of the solar atmosphere and its variation at different layers, although crucial for a comprehensive understanding of the dynamics of the solar magnetic field, has been a subject to contradictory results…
We demonstrate that the current helicity observed in solar active regions traces the magnetic helicity of the large-scale dynamo generated field. We use an advanced 2D mean-field dynamo model with dynamo saturation based on the evolution of…
Here we review the recent progress made in the detection, examination, characterisation and interpretation of oscillations manifesting in small-scale magnetic elements in the solar photosphere. This region of the Sun's atmosphere is…
The Sun is replete with magnetic fields, with sunspots, pores and plage regions being their most prominent representatives on the solar surface. But even far away from these active regions, magnetic fields are ubiquitous. To a large extent,…
Oscillations in sunspot umbrae exhibit remarkable differences between the photosphere and chromosphere. We evaluate two competing scenarios proposed for explaining those observations: a chromospheric resonant cavity and waves traveling from…
We study the dynamical and statistical properties of turbulent cross-helicity (correlation of the aligned fluctuating velocity and magnetic field components). We derive an equation governing generation and evolution of the turbulent…
In this study, the non-potential magnetic field parameters of active region NOAA 9077 are investigated; this AR experienced a super-strong X5.7 solar flare. Using advanced extrapolation techniques, the 3D magnetic field structure from…
The structure and energy balance of the solar chromosphere remain poorly known. We have used the imaging spectrometer IBIS at the Dunn Solar Telescope to obtain fast-cadence, multi-wavelength profile sampling of Halpha and Ca II 854.2 nm…
Heliospheric imagers offer the promise of remote sensing of large-scale structures present in the solar wind. The STEREO/HI-2 imagers, in particular, offer high resolution, very low noise observations of the inner heliosphere but have not…
Solar pores are strongly magnetized regions lacking a photospheric penumbra and characterized by predominantly vertical magnetic fields. We present a multi-line study of flashes in a solar pore using high-resolution observations from the…
Solar torsional oscillations are migrating bands of slower- and faster-than-average rotation, which are strongly related to the Sun's magnetic cycle. We perform a long-term study (16 yr) of hemispherical asymmetry in solar torsional…
The longitudinal asymmetry of the photospheric magnetic field distribution is studied on the basis of the data of the Kitt Peak National Solar Observatory (synoptic maps for the period 1976 - 2016). The method of vector summing of magnetic…
Solar wind backmapping is a critical technique for analyzing the origin of the solar wind and space weather events by correlating in situ measurements with solar remote-sensing observations. This technique typically traces magnetic field…
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…
Several studies have reported magnetic field fluctuations associated with umbral shock waves. We aim to study the properties and origin of magnetic field fluctuations in the umbral chromosphere. Temporal series of spectropolarimetric…