Search Publications
Observed dispersive properties of the slow magnetoacoustic waves propagating in coronal fan loops above sunspots
Zhao, Junwei; Chen, Ruizhu; Wang, Tongjiang
Recurrent and propagating intensity perturbations are frequently observed in extreme ultraviolet (EUV) channels along coronal fan loops above sunspots, and these perturbations are suggested to be slow magnetoacoustic waves. Numerous studies have been conducted to investigate their propagation speeds, damping, and excitation sources; however, there…
Doppler signature of a possible termination shock in an off-limb solar flare
Chen, Bin; Yu, Sijie; Matthews, Sarah A. +2 more
We report striking Doppler velocity gradients observed during the well-observed 2017 September 10 solar flare, and argue that they are consistent with the presence of an above-the-looptop termination shock beneath the flare current sheet. Observations from the Hinode Extreme-ultraviolet Imaging Spectrometer measure plasma sheet Doppler shifts up t…
Dynamics and structure of network magnetic fields: supergranular vortex expansion-contraction
Chian, Abraham C. -L.; Rempel, Erico L.; Gošić, Milan +1 more
We report on the formation of a large magnetic coherent structure in a vortex expansion-contraction interval, resulting from the merger of two plasmoids driven by a supergranular vortex observed by Hinode in the quiet-Sun. Strong vortical flows at the interior of vortex boundary are detected by the localized regions of high values of the instantan…
Concurrent kink and sausage waves in a crescent-shaped structure over a limb prominence
Ghiasi, Maryam; Dadashi, Neda; Ebadi, Hossein
A Crescent-shaped prominence Structure (CS) over the solar west limb is studied using Extreme Ultra-Violet (EUV) Imaging Spectrometer/Hinode and Atmospheric Imaging Assembly (AIA)/Solar Dynamics Observatory (SDO). First, the time-varying positions of the top and bottom borders of the CS, along with its central axis, are derived. Time evolutions of…
Time evolution of X-ray bright points observed with NuSTAR
Krucker, Säm; White, Stephen M.; Grefenstette, Brian W. +5 more
We present analysis on two X-ray bright points observed over several hours during the recent solar minimum (2020 February 21 and 2020 September 12-13) with the Nuclear Spectroscopic Telescope Array (NuSTAR), a sensitive hard X-ray imaging spectrometer. This is so far the most detailed study of bright points in hard X-rays, emission which can be us…
Unipolar solar flares as a manifestation of 'topological' magnetic reconnection
Dumin, Yurii V.; Somov, Boris V.
Solar flares - the most prominent manifestation of solar activity - typically manifest themselves as a single or a set of luminous arcs (magnetic flux tubes) rooted in regions of opposite polarity in the photosphere. However, a careful analysis of archival data from the Hinode satellite reveals occasional surprising cases of flaring arcs whose foo…
Probing solar wind velocity from simultaneous superior solar conjunction radio science experiments of BepiColombo and Akatsuki missions
Imamura, T.; Shiota, D.; Iess, L. +5 more
A radio link directly probing the inner solar corona offers the possibility to characterize solar wind properties, including velocity, density, turbulence, and even the axial ratio. In this study, we leveraged radiometric data obtained during a joint superior solar conjunction of the ESA/JAXA BepiColombo mission and the JAXA Akatsuki mission. Our …
Intensification of magnetic field in merging magnetic flux tubes driven by supergranular vortical flows
Chian, Abraham C. -L.; Silva, Suzana S. A.; Rempel, Erico L. +2 more
The spatiotemporal dynamics of vorticity and magnetic field in the region of a photospheric vortex at a supergranular junction of the quiet Sun is studied, using Hinode's continuum intensity images and longitudinal magnetograms. We show that in a 30-min interval during the vortex lifetime, the magnetic field is intensified at the centres of two me…
The role of cooling induced by mixing in the mass and energy cycles of the solar atmosphere
Hillier, Andrew; Snow, Ben; Arregui, Iñigo
In many astrophysical systems, mixing between cool and hot temperature gas/plasma through Kelvin-Helmholtz-instability-driven turbulence leads to the formation of an intermediate temperature phase with increased radiative losses that drive efficient cooling. The solar atmosphere is a potential site for this process to occur with interaction betwee…
Solar coronal magnetic field measurements using spectral lines available in Hinode/EIS observations: strong and weak field techniques and temperature diagnostics
Chen, Yajie; Tian, Hui; Bai, Xianyong +4 more
Recently, it has been proposed that the magnetic-field-induced transition (MIT) in Fe X can be used to measure coronal magnetic field strengths. Several techniques, the direct line ratio technique and the weak and strong magnetic field techniques, are developed to apply the MIT theory to spectroscopic observations taken by EUV Imaging Spectrometer…