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We propose a new method of the automated identification of current sheets (CSs) that represents a formalization of the visual inspection approach employed in case studies. CSs are often identified by eye via the analysis of characteristic…

Space Physics · Physics 2021-07-27 Olga Khabarova , Timothy Sagitov , Roman Kislov , Gang Li

In the corona, plasma is accelerated to hundreds of kilometers per second, and heated to temperatures hundreds of times hotter than the Sun's surface, before it escapes to form the solar wind. Decades of space-based experiments have shown…

We study the nature of quiet-Sun oscillations using multi-wavelength observations from TRACE, Hinode, and SOHO. The aim is to investigate the existence of propagating waves in the solar chromosphere and the transition region via analyzing…

Solar and Stellar Astrophysics · Physics 2012-09-27 G. R. Gupta , S. Subramanian , D. Banerjee , M. S. Madjarska , J. G. Doyle

We report three-minute oscillations in the solar chromosphere driven by a strong downflow event in a sunspot. We used the Fast Imaging Solar Spectrograph of the 1.6 m New Solar Telescope and the Interface Region Imaging Spectrograph (IRIS).…

Solar and Stellar Astrophysics · Physics 2016-04-27 Hannah Kwak , Jongchul Chae , Donguk Song , Yeon-Han Kim , Eun-Kyung Lim , Maria S. Madjarska

Image alignment plays a crucial role in solar physics research, primarily involving translation, rotation, and scaling. \G{The different wavelength images of the chromosphere and transition region have structural complexity and differences…

Instrumentation and Methods for Astrophysics · Physics 2025-03-17 Yun Wang , KaiFan Ji , Zhenyu Jin , Hui Liu

In time-distance helioseismology, the time signals (Doppler shifts) at two points on the solar surface, separated by a fixed angular distance are cross-correlated, and this leads to a wave packet signal. Accurately measuring the travel…

Astrophysics · Physics 2011-02-11 R. Nigam , A. G. Kosovichev , P. H. Scherrer

We study Doppler velocity measurements at multiple heights in the solar atmosphere using a set of six filtergrams obtained by the Helioseismic magnetic Imager on board the Solar Dynamics Observatory. There are clear and significant phase…

Solar and Stellar Astrophysics · Physics 2014-01-15 Kaori Nagashima , Laurent Gizon , Aaron Birch , Björn Löptien , Sebastien Couvidat , Bernhard Fleck

Although the differential rotation rate on the solar surface has long been studied using optical and extreme ultraviolet (EUV) observations, associating these measurements to specific atmospheric heights remains challenging due to the…

Solar and Stellar Astrophysics · Physics 2025-07-04 Srinjana Routh , Anshu Kumari , Vaibhav Pant , Jaydeep Kandekar , Dipankar Banerjee , Mohd. Saleem Khan , Dibya Kirti Mishra

New data was obtained for a frequency band that had not been so well-studied for sea surface probing applications before. During the described 2-weeks sea experiment 1-3 kHz tonal pulses were emitted from a platform, located on the northern…

Atmospheric and Oceanic Physics · Physics 2022-05-31 Alexey V. Ermoshkin , Dmitry A. Kosteev , Alexander A. Ponomarenko , Dmitry D. Razumov , Mikhail B. Salin

There have been ubiquitous observations of wave-like motions in the solar atmosphere for decades. Recent improvements to space- and ground-based observatories have allowed the focus to shift to smaller magnetic structures on the solar…

Solar and Stellar Astrophysics · Physics 2014-08-21 N. Freij , E. M. Scullion , C. J. Nelson , S. Mumford , S. Wedemeyer , R. Erdélyi

We present a new method for helioseismic diagnostics of the three-dimensional structure of sound speed, magnetic fields and flow velocities in the convection zone by inversion of acoustic travel-time data. The data are measurements of the…

Solar and Stellar Astrophysics · Physics 2018-06-11 A. G. Kosovichev , T. L. Duvall

In stratified atmospheres, acoustic waves can only propagate if their frequency is above the cutoff value. Different theories provide different cutoff values. We developed an alternative method to derive the cutoff frequency in several…

Solar and Stellar Astrophysics · Physics 2020-07-29 T. Felipe , C. R. Sangeetha

Being able to image active regions on the Sun's far side is useful for modeling the global-scale magnetic field around the Sun, and for predicting the arrival of major active regions that rotate around the limb onto the near side.…

Solar and Stellar Astrophysics · Physics 2020-01-08 Junwei Zhao , Dominick Hing , Ruizhu Chen , Shea Hess Webber

We perform a validation study of the latest version of the Alfv\'{e}n Wave Solar atmosphere Model (AWSoM) within the Space Weather Modeling Framework (SWMF). To do so, we compare the simulation results of the model with a comprehensive…

We review novel data analysis techniques developed or adapted for the field of coronal seismology. We focus on methods from the last ten years that were developed for extreme ultraviolet (EUV) imaging observations of the solar corona, as…

The launch of the Hinode satellite has allowed for seeing-free observations at high-resolution and high-cadence making it well suited to study the dynamics of quiescent prominences. In recent years it has become clear that quiescent…

Solar and Stellar Astrophysics · Physics 2015-06-17 A. Hillier , R. J. Morton , R. Erdélyi

The solar photosphere provides us with a laboratory for understanding turbulence in a layer where the fundamental processes of transport vary rapidly and a strongly superadiabatic region lies very closely to a subadiabatic layer. Our tools…

The quantity of small scale solar photovoltaic (PV) arrays in the United States has grown rapidly in recent years. As a result, there is substantial interest in high quality information about the quantity, power capacity, and energy…

Computer Vision and Pattern Recognition · Computer Science 2016-10-03 Jordan M. Malof , Kyle Bradbury , Leslie M. Collins , Richard G. Newell

The high spatial and time resolution data obtained with SDO/AIA for the sunspot in active region NOAA 11131 on 08 December 2010 were analysed with the time-distance plot technique and the pixelised wavelet filtering method. Oscillations in…

Solar and Stellar Astrophysics · Physics 2014-09-17 R. Sych , V. M. Nakariakov

We present a new method for performing differential emission measure (DEM) inversions on narrow-band EUV images from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). The method yields positive definite…

Solar and Stellar Astrophysics · Physics 2015-07-15 Mark C. M. Cheung , P. Boerner , C. J. Schrijver , P. Testa , F. Chen , H. Peter , A. Malanushenko