This work investigates the density of in-falling prominence material following the 7th June 2011 eruption. Both the evolution and the distribution of the density is analysed in five discreet “blobs” of material. The density appears to be remarkably uniform, both spatially within the blobs, and temporally over the course of the descent of each, although a slight concentration of material towards the leading edge is noted in some cases. Online material is available at bit.ly/jackblob

Using the multi-wavelength data from AIA/SDO, we report a failed filament eruption, which was associated with an X1.9 flare, but without any distinct CME, coronal dimming or EUV wave. Some magnetic arches above the filament was observed distinctly in EUV channels, especially in 94 Å and 131 Å, before and during the filament eruption. Our results show that the overlying arcades expanded along with the ascent of the filament at first until they reached a projected height of about 49 Mm above the Suns surface, where they stopped. The following filament material was observed to be confined by the stopped EUV arches and not to escape from the Sun. These results support that the overlying arcades play an important role in preventing the filament to erupt outward successfully.

We analyze a prominence-like cool plasma structure as observed by Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). We perform the Differential Emission Measure (DEM) analysis using various filters of AIA, and also deduce the temperature and density structure in and around the observed flux-tube. In addition to deducing plasma parameters, we also find an evidence of multiple harmonics of fast magnetoacoustic kink waves in the observed prominence-like magnetic structure. Making use of estimated plasma parameters and observed wave parameters, under the baseline of MHD seismology, we deduce magnetic field in the flux-tube. The wave period ratio P1/P2 = 2.18 is also observed in the flux-tube, which carries the signature of magnetic field divergence where we estimate the tube expansion factor as 1.27. We discuss constraints in the estimation of plasma and magnetic field properties in such a structure in the current observational perspective, which may shed new light on the localized plasma dynamics and heating scenario in the solar atmosphere.

The influence of the electron κ - distributions on the differential emission measure (DEM) of the prominence-corona transition region (PCTR) derived from observed line intensities has been investigated. An important consequence of the κ - distribution is formation of the emission lines in much wider temperature ranges. The implications for the formation temperature of the observed SDO/AIA band emissions are shown.

We use a 2.5-dimensional, fully thermodynamically and magnetohydrodynamically compatible model to imitate the formation process of normal polarity prominences on top of initially linear force-free arcades above photospheric neutral lines. In magnetic arcades hosting chromospheric, transition region, and coronal plasma, we perform a series of numerical simulations to do a parameter survey for multi-dimensional evaporation-condensation prominence models. The investigated parameters include the fixed angle of the magnetic arcade, the strength and spatial range of the localized chromospheric heating.

Stable long lived solar filaments during their lives can approach each other, merge, and form circular structures. Since filaments follow large scale polarity inversion lines of the photospheric magnetic field, their evolution reflects changes of the photospheric field distribution. On the other hand, filament interaction depends on their internal magnetic structure reviled in particular by filament chirality. Possibility of magnetic field line reconnection of neighbor filaments is discussed. Many examples of connectivity changes in a course of photospheric field evolution were found in our analysis of daily Hα filtergrams for the period of maximum activity of the solar cycle 23.

We have developed a suite of forward-modeling IDL codes (FORWARD) to convert analytic models or simulation data cubes into coronal observables, allowing a direct comparison with observations. Observables such as extreme ultraviolet, soft X-ray, white light, and polarization images from the Coronal Multichannel Polarimeter (CoMP) can be reproduced. The observer's viewpoint is also incorporated in the FORWARD analysis and the codes can output the results in a variety of forms in order to easily create movies, Carrington maps, or simply observable information at a particular point in the plane of the sky. We present a newly developed front end to the FORWARD codes which utilizes IDL widgets to facilitate ease of use by the solar physics community. Our ultimate goal is to provide as useful a tool as possible for a broad range of scientific applications.

This article comments on the results of a new, rapid, and flexible manual method to map on-disk individual coronal loops of a two-dimensional EUV image into the three-dimensional coronal loops. The method by Gary, Hu, and Lee (2013) employs cubic Bézier splines to map coronal loops using only four free parameters per loop. A set of 2D splines for coronal loops is transformed to the best 3D pseudo-magnetic field lines for a particular coronal model. The results restrict the magnetic field models derived from extrapolations of magnetograms to those admissible and inadmissible via a fitness parameter. This method uses the minimization of the misalignment angles between the magnetic field model and the best set of 3D field lines that match a set of closed coronal loops. We comment on the implication of the fitness parameter in connection with the magnetic free energy and comment on extensions of our earlier work by considering the issues of employing open coronal loops or employing partial coronal loop.

We present the results of detailed study of a set of activities developed on one of three enclosed sectors of solar region during the period of February 07–13, 2012. We found the sequence of certain topological perturbations of whole coronal holes (CHs) and their surroundings associated to the eruption of nearby prominence and subsequent Coronal Mass Ejections (CMEs). Especially, we observe the emergence of small bright points (BPs) and the formation of dimming regions (DRs) close to the filament's channel associated with a pre–evolution of filament/prominence eruption, whereas BPs disappearance and the shrinkage of CH we found associated with the post-eruption evolution of prominence and of CME.

Using the eclipse observations, we construct the maps of quiescent prominence temperatures, electron densities, pressures and geometrical thicknesses. For this we use the RGB signal of prominence visible-light emission detected during the total solar eclipse on August 1, 2008 in Mongolia, and quasi-simultaneous Hα spectra taken at Ondřejov observatory. The method of disentangling the electron density and effective geometrical thickness was described by Jejčič & Heinzel (2009) and is used here for the first time to analyse the spatial variations of various prominence parameters.

Real-time monitoring of filaments is essential for the prediction of their eruption and the ensuing coronal mass ejection (CME). We apply an automated algorithm for the detection and tracking of filaments in full-disc Hα images to obtain their physical attributes. This provides an accurate onset time of the eruption, and also allows us to study the physical characteristics of the erupting filaments in an objective manner.

In this paper, we present RHESSI and TRACE observations of multiple flare activity that occurred in the active region NOAA 10656 on 2004 August 18. Out of four successive flares, there were three events of class-C while the final event was a major X1.8 solar eruptive flare. During localized C-class flares, the filament undergoes slow yet crucial morphological evolution. The filament eruption is accompanied with an X1.8 flare during which multiple HXR bursts are observed up to 100–300 keV energies. From the location, timing, strength, and spectrum of HXR emission, we conclude that the prominence eruption is driven by the distinct events of magnetic reconnection occurring in the current sheet below the erupting prominence. These multi-wavelength observations also provide evidence for tether-cutting reconnection as the triggering mechanism for filament eruption and associated X-class flare.

The successes of magnetic measurements in faint objects located near very bright ones are strongly depending on the stray light in the telescope. We propose a mask with a variable transmission placed on the primary optics of a telescope. Our computations of the stray light in such a telescope indicate that the calculated coronagraphic factor of improvement, K, would increase at least by 2 orders of magnitude compared to the Lyot-type coronagraph.

On 20 August 2010 an energetic disturbance triggered damped large-amplitude longitudinal (LAL) oscillations in almost an entire filament. In the present work we analyze this periodic motion in the filament to characterize the damping and restoring mechanism of the oscillation. Our method involves placing slits along the axis of the filament at different angles with respect to the spine of the filament, finding the angle at which the oscillation is clearest, and fitting the resulting oscillation pattern to decaying sinusoidal and Bessel functions. These functions represent the equations of motion of a pendulum damped by mass accretion. With this method we determine the period and the decaying time of the oscillation. Our preliminary results support the theory presented by Luna and Karpen (2012) that the restoring force of LAL oscillations is solar gravity in the tubes where the threads oscillate, and the damping mechanism is the ongoing accumulation of mass onto the oscillating threads. Following an earlier paper, we have determined the magnitude and radius of curvature of the dipped magnetic flux tubes hosting a thread along the filament, as well as the mass accretion rate of the filament threads, via the fitted parameters.

Both the origin of the quiescent prominences and their eruption related to CMEs are still a matter of extended studies. The small scale dynamic aspects like vortex structures and counter- flows are now seriously taken into account having in mind that the flows are a good proxy of the line of force of the omnipresent but rather unknown in detail force free or not magnetic field. Large scale vortex has been detected in a high latitude prominence observed on November 13- 14, 2011 before its eruption.

Both the origin of the quiescent prominences and their eruption related to CMEs event are still a matter of extended studies. The case of high latitudes quiescent prominences producing slow CMEs can be considered as a potential component of the slow wind. A high latitude prominence was observed on November 13 - 14, 2011. A schematic representation of flux rope is proposed to describe the magnetic structure of the prominence prior to its eruption.

We have observed a quiescent prominence with the Hinode Solar Optical Telescope (SOT) (Ca II and Hα lines), Sacramento Peak Dunn Solar Telescope using the Universal Birefringent Filter (DST/UBF, in Hα, Hβ and Sodium-D lines), THEMIS (Télescope Héliographique pour l Etude du Magnétisme et des Instabilités Solaires/MTR (Multi Raies) spectromagnetograph (He D3), and the Solar Dynamics Observatory Atmospheric Imaging Assembly (SDO/AIA) in EUV over a 4 hour period on 2012 October 10. The small fields of view of the SOT, DST, and MTR are centered on a large prominence footpoint extending towards the surface. This feature appears in the larger field of view of the AIA/304 Å filtergram as a large, quasi-vertical pillar with loops on each side. The THEMIS/MTR data indicate that the magnetic field in the pillar is essentially horizontal and the observations in the optical domain show a large number of horizontally aligned features in the pillar. The data are consistent with a model of cool prominence plasma trapped in the dips of horizontal field lines. The SOT and DST data show what appear to be moving wave pulses. These pulses, which include a Doppler signature, move vertically, perpendicular to the field direction, along quasi-vertical columns of horizontal threads in the pillar. The pulses have a velocity of propagation of about 10 km/s, a wavelength about 2000 km in the plane of the sky, and a period about 280 sec. We interpret these waves in terms of fast magnetosonic waves.

High-resolution spectra of a giant solar quiescent filament were taken with the Echelle spectrograph at the Vacuum Tower Telescope (VTT; Tenerife, Spain). A mosaic of various spectroheliograms (Hα, Hα±0.5 Å and Na D2) were chosen to examine the filament at different heights in the solar atmosphere. In addition, full-disk images (He i 10830 Å and Ca ii K) of the Chromspheric Telescope and full-disk magnetograms of the Helioseismic and Magnetic Imager were used to complement the spectra. Preliminary results are shown of this filament, which had extremely large linear dimensions (~740″) and was observed in November 2011 while it traversed the northern solar hemisphere.

The EVE instrument on SDO is making accurate measurements of the solar spectral irradiance in the EUV between 30 and 1069 Å, with 1 Å spectral resolution and 10 s sampling rate. These data define solar variability in the “Sun-as-a-star” mode and reveal many interesting kinds of variation. Its high sensitivity also makes it suitable for spectroscopic diagnostics of solar features such as flares. Here we present EVE's potential contribution to the diagnostics of large-scale, slowly evolving features such as prominences and active regions, and what we can learn from this.

We present SDO/AIA observations of a potentially novel type of prominence, called “funnel prominence”, that forms out of coronal condensation at magnetic dips.

They can drain a large amount of mass (up to ~1015 g day−1) and may play an important role as return flows of the chromosphere-corona mass cycle.