Related papers: Behaviour of oscillations in loop structures above…
We investigate the oscillatory properties of the quiet solar chromosphere in relation to the underlying photosphere, with particular regard to the effects of the magnetic topology. We perform a Fourier analysis on a sequence of…
Three- and five-minute oscillations are commonly found in any sunspot. As they are modulated by the internal thermal and magnetic structures of a sunspot, therehence, they could be used as an effective tool for sunspot seismology. In this…
Recent observations show a variety of oscillation modes in the corona. Early non-imaging observations in radio wavelengths showed a number of fast-period oscillations in the order of seconds, which have been interpreted as fast sausage mode…
We study chromospheric oscillations including umbral flashes and running penumbral waves in a sunspot of active region (AR) using scanning spectroscopy in H-alpha and Ca II 8542A, with the Fast Imaging Solar Spectrograph (FISS) at the 1.6…
Solar five-minute oscillations have been detected in the power spectra of two six-day time intervals from soft X-ray measurements of the Sun observed as a star using the Extreme Ultraviolet Spectrophotometer (ESP) onboard the Solar Dynamics…
Using long-duration observations in the He II 304 Angstrom passband of the Solar and Heliospheric Observatory (SOHO) Extreme-ultraviolet Imaging Telescope (EIT) we investigate the spatial and temporal appearance of impulsive intensity…
We present the observations of an extreme-ultraviolet (EUV) wave, which originated from the active region (AR) NOAA 12887 on 28 October 2021 and its impact on neighbouring loops. The event was observed by the Atmospheric Imaging Assembly…
We provide estimates of the wave energy reaching the solar chromosphere and corona in a network-like magnetic field topology, including a coronal null point. The waves are excited by an instantaneous strong subphotospheric source and…
We examine continuous measurements of the high-degree acoustic mode frequencies of the Sun covering the period from 2001 July to June 2014. These are obtained through the ring-diagram technique applied to the full-disk Doppler observations…
We analyse 3-min oscillations of microwave and EUV emission generated at different heights of a sunspot atmosphere, studying the amplitude and frequency modulation of the oscillations, and its relationship with the variation of the spatial…
Aims. We study the coherency of solar spicules intensity oscillations with increasing height above the solar limb in quiet Sun, active Sun and active region using observations from HINODE/SOT. Existence of coherency up to transition region…
We use high-resolution images of the sun obtained by the SDO/AIA instrument to study the evolution of the coronal loops in a flaring solar active region. During 15 February 2011 a X-2.2 class flare occurred in NOAA 11158, a…
The solar active region NOAA 11719 produced a large two-ribbon flare on 11 April 2013. We have investigated the sudden variations in the photospheric magnetic fields in this active region during the flare employing the magnetograms obtained…
We present observations of high temperature emission in the core of a solar active region using instruments on Hinode and SDO. These multi-instrument observations allow us to determine the distribution of plasma temperatures and follow the…
For the purpose of investigating the differential rotation of the solar corona, we analyzed ultraviolet (UV) spectral line observations acquired on both the east and west limbs at 1.7 $R_{\odot}$ by SOHO/UVCS during the solar minimum…
Rapidly decaying long-period oscillations often occur in hot coronal loops of active regions associated with small (or micro-) flares. This kind of wave activity was first discovered with the SOHO/SUMER spectrometer from Doppler velocity…
Waves are important for the heating of the solar corona and the acceleration of the solar wind. We have examined a long spectral time series of a northern coronal hole observed on the 20th October 1996, with the SUMER spectrometer onboard…
Recent SECCHI COR2 observations on board STEREO-A spacecraft have detected density structures at a distance of 2.5--15~R propagating with periodicity of about 90~minutes. The observations show that the density structures probably formed in…
Wave theories of heating the chromosphere, corona, and solar wind due to photospheric fluctuations are strengthened by the existence of observed wave coherency up to the transition region (TR). The coherency of solar spicules' intensity…
The propagation and the evolution of Alfvenic pulses in the solar coronal arcades is investigated by means of MHD numerical simulations. Significant transverse oscillations in coronal loops, triggered by nearby flare events, are often…