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The disparate nature of thermal-nonthermal energy partition during weak flares compared to that during the large flares is still an open issue and quantifying the relative productivity of multi-wavelength emission during weak flares can enable inferring the underlying energy release mechanism. Therefore, we analyze multi-wavelength emission from ∼150 flares during September 20-25, 2021, commonly observed from Spectrometer Telescope for Imaging X-rays (STIX) (at ∼0.6 AU), STEREO-A, GOES, and SDO observatories (significant overlap of observing field-of-view). The ratio (Qf ) of HXR (>12 keV) fluence (Fhxr ) and SXR (4-10 keV) flux (Fsxr), at the maximum of Fsxr (tp), is derived to quantify the relative productivity of HXR and SXR emission during flares. The variation of Qf with Fsxr enabled us to quantitatively identify the cases of strongly non-thermal (cold) and highly thermal (hot) flares. The identification of the source active region using the EUV images (from AIA) revealed the uniform behavior of different active regions in producing cold and hot flares. Besides, thermal-nonthermal plasma parameters as estimated by spectral-fit of STIX and XSM observations indicate a possible role of pre-flare density in flare loops to be resulting in disparate thermal-nonthermal emission partition. Therefore, we conduct case studies of flares of the aforementioned types by – synthesizing the X-ray images from STIX observations – analyzing the E/UV images, and magnetograms, and — performing the hydrodynamical simulations using the 1D Palermo-Harvard code. With such a multi-wavelength analysis of an ensemble of weak flares, we probe the energy release mechanism and evaluate the same in the framework of the standard model of energy release during large flares.

Solar Hard X-Ray (HXR) emission is observed typically in the form of localized, rather compact sources. Majority of these sources are flare related, however there is growing evidence, observational and theoretical, that we can expect HXR emission from places not directly related to primary energy release regions. From this point of view, failed eruptions are phenomena which are very interesting. Failed eruptions are events which at an early phase develop like a typical eruption which evolves into CME. However, for unclear reasons these eruptions stop abruptly somewhere in the solar corona. Many mechanisms are suspected to be responsible for stopping an eruption i.e. kink instability leading to stable configuration of erupting flux tube, magnetic tension within erupting structure or interaction and reconnection with an overlying coronal magnetic field. The last one may lead to electron acceleration and production of high temperature regions emitting in the HXR. There are only a few observations, from past instruments, showing some evidence of HXR production in failed eruptions. Recently, the Solar Orbiter has been launched giving a completely new perspective for observation and analysis of coronal dynamic events. Apart from others, it carries onboard Extreme-Ultraviolet Imager (EUI) and Spectrometer/Telescope for Imaging X-rays (STIX) telescopes open an opportunity to understand the physics of failed eruptions. The new EUV and HXR observations are important for at least two reasons. First, SO can approach the Sun closer than 0.3 a.u. which increase spatial resolution and sensitivity of telescopes, giving ocasion for registering weak HXR sources which can not be observed with previous instruments. Second, SDO/AIA instrument operating on the Earth orbit can provide stereoscopic context for SO/EUI images which may help to investigate deeper the geometry of the eruption and causes of its braking. Here, we present a very well observed flare accompanied by a failed eruption. The event occurred when longitudinal separation of the Earth and SO was 17 degrees. From the Earth perspective the event was visible very close to the west limb of a solar disc. For SO it was a behind-the-limb event with occulted footpoints which gave us a very good view, especially in the HXR range, of emission coming from the solar corona. During a flare's impulsive phase, the eruption accelerated to the velocity of a few hundreds kilometers per second and after six minutes it stopped abruptly at the height of 100 000 km above the solar surface. The eruption reconnected with overlying coronal loops leading to occurrence of at least three regions observed by STIX. The lowest source seems to be a typical, flare related coronal source, possibly consisting of two spatially unresolved sources located close to the primary reconnection site. The other two sources are located higher in the corona where reconnection of the eruption with an overlying magnetic field was observed. These sources behave significantly differently than the lowest source. Namely, their evolution is more gradual and seems to be driven by direct heating not the evaporation of chromospheric plasma which is a case for the lowest source.

Energy spectra of X-ray solar flares observed by the Spectrometer-Telescope for Imaging X-rays (STIX) onboard the Solar Orbiter consist of both thermal and non-thermal parts. The thermal part is present in all solar events. When the non-thermal part of the energy spectrum begins to dominate, we can expect detection in interplanetary space of high-energy electron beams that have escaped the coronal loops. When hard X-ray flares are detected solar type III radio bursts are registered frequently with their numerous modifications like drift pairs, U-type, and structured bursts. The e-CALLISTO simple worldwide radio antenna stations allow us to identify the existence of non-thermal components in the energy spectra of strong X-ray flares. At the same time, some X-ray flares are accompanied by ejections of energetic ions including heavy ions. The specific features in X-ray bursts responsible for events with simultaneous light and heavy particle stream generation are still unclear compared with those with electron emission only. We present preliminary results of observations gathered in December 2022 and cross-analysis of data on energetic light and heavy particle fluxes and X-ray flare parameters. The end of 2022 was distinguished by moderate to high solar activity, the presence of three periods with enhanced proton and heavy-ion fluxes at the beginning of the month, in the middle, and on 25-26 December. We demonstrate also the presence of narrow directed electron beams detected by the Electron Proton Telescope (EPT) of EPD for selected events mentioned above, and heavy ions detected by the Suprathermal Ion Spectrograph (SIS) of EPD.

In this work we aimed to develop the image reconstruction algorithm without any analytical simplifications and restrictions. In our method we abandon Fourier’s approach to image reconstruction, and instead use the number of counts recorded in each detector pixel, and then reconstruct each image using a classical Richardson-Lucy algorithm. Among similar works performed in the past, our approach is based, for the first time, on the real geometry of STIX. We made a preliminary analysis of expected differences in STIX imaging which may occur due to usage of slightly different geometries. The other difference is that we use single-pixel-response maps. Namely, knowing the instrument geometry we are able to calculate the detector response for point sources covering entire the solar disc. Next, we iteratively combine them with varying weights until the best match between reconstructed and observed detector responses is achieved. Preliminary tests revealed that the developed algorithm reproduces high quality images. The algorithm is moderately fast, but the result comparable to CLEAN algorithm is obtained within 20-50 iteration steps which takes less than 2 seconds on typical portable computer configuration. The location, size and intensity of reconstructed sources are very close to simulated ones. Therefore the algorithm is very well suited for the detailed photometry of the solar HXR sources. Moreover, its simplicity allows to improve photon transmission calculation in case of any grids uncertainties measured after the launch.

Osteochondral defects of the knee are common in orthopaedic patients. They are challenging to treat, especially in young, highly demanding patients who do not qualify for arthroplasty. Among the many possibilities to treat osteochondral lesions presented so far, none is ideal. Because of the poor healing potential of cartilage, treatment outcomes significantly worsen with larger lesions. The treatment of large defects usually requires expensive solutions, sometimes including second-stage surgery. Using mesenchymal stem cell transplantation and cancellous bone autografts, the technique presented here for osteochondral lesion reconstruction can be effectively used to treat large osteochondral lesions in a single-stage procedure.

The aim of the research was to explore the possibilities of using the Asynchronous Delay Tap Sampling (ADTS) and Convolutional Neural Network (CNN) methods to monitor the simultaneously occurring phenomena in the physical layer of the optical network. The ADTS method was used to create a data sets showing the combination of Chromatic Dispersion (CD), Crosstalk and Optical to Signal Noise Ratio (OSNR) as optical disturbances in graphic form. Data were generated for 10 GB/s, Non-return-to-zero On–off keying (NRZ-OOK) and Differential Phase Shift Keying (DPSK) modulation and bit delays: 1 bit, 0.5 bit and 0.25 bit. A total of 6 data sets of 62,000 images each were obtained. The learning process was carried out for the number of epochs 50 and 1000. From the obtained learning results of the network, models with the best $$R^{2}$$ R 2 matching factor were selected. The learned models were further used to study the recognition of three phenomena simultaneously. The tests were carried out on sets of 2500 images in a combination of interference in the following ranges: 400–1600 ps/nm for CD and 10–30 dB for Crosstalk and OSNR. Very good results were obtained for recognizing simultaneously occurring phenomena using models learned up to 1000 epoch. Accuracy of over 99% was obtained for CD and Crosstalk for both modulations. In the case of the OSNR phenomenon, slightly weaker results were obtained above 96% in most cases. For models taught up to 50 epoch, very good results were obtained for the CD phenomenon (over 99%). For Crosstalk weaker results for OOK modulation were obtained. Poor results were obtained for the OSNR phenomenon, where recognition accuracy ranged from 50 to 80%, depending on the type of modulation and bit delay. Based on the conducted research, it was established that the use of ADTS and CNN methods enables monitoring of simultaneously occurring CD, Crosstalk and OSNR interference in the physical layer of the optical network, while maintaining the requirements for Optical Performance Monitoring systems. These requirements are met for network models learned up to 1000 epoch.

The aim of this study was to assess the treatment results of 90Y radiation synovectomy for chronic exudative synovitis of knee joints. The retrospective data consist of 394 consecutive knee radiation synovectomies performed using 6 mCi (222 MBq) of 90Y. The assessment included 3-point custom pain and joint mobility scale, evaluation of joint’s circumference, binary joint’s temperature evaluation, patellar ballottement test, indications for puncture and its volume in applicable cases. 21 cases had to be forfeited due to missing data regarding follow-up. The final analysis of 373 treatment procedures performed in 253 patients yielded following results—at 6 months after treatment, 80.9% of the patients reported at least partial pain relief (including 33.3% with complete pain relief), which increased to 86.7% at one year. The pain intensity decreased over time, however, the outcomes were worse in older patients. The probability of pain recurrence was 15% at 6 months, and 28% at one year. It was highest in post-traumatic synovitis, and lowest in pigmented villonodular synovitis. The circumference of the treated knee joints decreased over the course of follow-up, however, the decrease was significantly lower in older patients. The fraction of patients with full knee joint mobility increased from 34.6 to 40.6% at 6 months and 49.2% at one year. The percentage of patients that required articular puncture decreased from 62.8% at baseline to about 35.6% at 6 months, and 32.8% at one year. Positive patellar ballottement was found in 68.5% before treatment and remained at about 40–50% during the course of follow-up. The increased temperature of the joint was reported in 51.2% at baseline and decreased to 33% at 6 months and 28.3% at one year. (1) Radiation synovectomy is a safe and effective method of treatment in patients with exudative synovitis, however, the pain recurrence rate is significantly higher in post-traumatic exudative synovitis compared to pigmented villonodular, undifferentiated, and rheumatoid arthritis. (2) Our results suggest that older patients have worse treatment results with radiation synovectomy compared to younger patients.

Tibial plateau fractures occur in both old and young patients and may be caused by low-energy trauma, as well as high-energy trauma. Owing to the variety of injury mechanisms and fracture patterns, tibial plateau fractures are very challenging to treat. One of the most demanding fractures is the type III fracture according to the Schatzker classification, which is a pure depression of the lateral tibial plateau. Treatment with open surgical procedures is associated with vast soft-tissue trauma and prolonged recovery after surgery. Although soft-tissue trauma is minimized and visual control is improved throughout arthroscopy-assisted surgical procedures, internal fixation using buttress plates or lag screws is still required to reduce and fix the depressed plateau. We present an arthroscopy-assisted technique of reduction and fixation of the lateral tibial plateau fracture with 3 BioComposite interference screws (Arthrex, Munich, Germany) that provides a high amount of stability and reduces patient immobilization, allowing for faster rehabilitation., Technique Video Video 1 Arthroscopy-assisted management of Schatzker type III tibial plateau fracture reduction and stabilization. A right knee is being treated. At the beginning, the diagnosis is confirmed arthroscopically through standard anterolateral and anteromedial portals, and concomitant intra-articular lesions are excluded. Then, the whole procedure is performed using already created portals. With visualization through the anterolateral portal, an anterior cruciate ligament drill guide is inserted through the anteromedial portal and aimed in the center of depression on the surface of the lateral tibial plateau (LTP). The guidewire is fixed in the cortical bone layer to prevent its accidental movement. Under fluoroscopic control, a tibial tunnel is created, ending approximately 1 cm below the fracture line. A bone tamper is used to elevate the depressed part of the articular surface. Arthroscopic visualization and intraoperative radiographs are used to control the fracture reduction. When the proper articular surface reduction is achieved, the aiming wire is introduced into the bone tunnel. Under fluoroscopic control, the first BioComposite interference screw is placed under the elevated articular surface. Then, the aiming wire is withdrawn from the first BioComposite interference screw, but it remains in the bone tunnel. Afterward, another 2 BioComposite interference screws are sequentially introduced and placed underneath the first screw, positioning it parallel to the articular surface. By use of arthroscopic visualization, overcorrection of the fracture should be ruled out.

We present a description of the recent advances in the development of the KORTES assembly -- the first solar oriented mission designed for the Russian segment of International Space Station. The KORTES consists of several imaging and spectroscopic instruments collectively covering a wide spectral range extending from extreme ultraviolet (EUV) wavelengths to X-rays. The EUV telescopes inside KORTES will trace the origination and dynamics of various solar phenomena, e.g. flares, CMEs, eruptions etc. EUV spectra provided by grazing-incidence spectroheliographs will enable precise DEM-diagnostics during these events. The monochromatic X-ray imager will observe the formation of hot plasma in active regions and outside them. The SolpeX module inside KORTES will offer an opportunity to measure fluxes, Doppler shifts and polarization of soft X-ray emission both in lines and continuum. SolpeX observations will contribute to studies of particle beams and chromospheric evaporation. The instrumentation of KORTES will employ a variety of novel multilayer and crystal optics to be discussed. The deployment of KORTES is planned of 2024.

The Spectrometer/Telescope for Imaging X-rays (STIX) is the HXR instrument onboard Solar Orbiter designed to observe solar flares over a broad range of flare sizes, between 4-150 keV. We report the first STIX observations of microflares recorded during the instrument commissioning phase in order to investigate the STIX performance at its detection limit. This first result paper focuses on the temporal and spectral evolution of STIX microflares occuring in the AR12765 in June 2020, and compares the STIX measurements with GOES/XRS, SDO/AIA, and Hinode/XRT. For the observed microflares of the GOES A and B class, the STIX peak time at lowest energies is located in the impulsive phase of the flares, well before the GOES peak time. Such a behavior can either be explained by the higher sensitivity of STIX to higher temperatures compared to GOES, or due to the existence of a nonthermal component reaching down to low energies. The interpretation is inconclusive due to limited counting statistics for all but the largest flare in our sample. For this largest flare, the low-energy peak time is clearly due to thermal emission, and the nonthermal component seen at higher energies occurs even earlier. This suggests that the classic thermal explanation might also be favored for the majority of the smaller flares. In combination with EUV and SXR observations, STIX corroborates earlier findings that an isothermal assumption is of limited validity. Future diagnostic efforts should focus on multi-wavelength studies to derive differential emission measure distributions over a wide range of temperatures to accurately describe the energetics of solar flares. Commissioning observations confirm that STIX is working as designed. As a rule of thumb, STIX detects flares as small as the GOES A class. For flares above the GOES B class, detailed spectral and imaging analyses can be performed., Comment: 19 pages, 11 figures

The thick-target model predicts that in flare foot points, we should observe lowering of HXR sources' altitude with increasing energy. The foot point of HXR sources result from the direct interaction of non-thermal electron beams with plasma in the lower part of the solar atmosphere, where the density increases rapidly. Therefore, we can estimate the plasma density distribution along the non-thermal electron beam directly from the observations of the altitude-energy relation obtained for the HXR foot point sources. The relation's shape is density-dependent and is also determined by the power-law distribution of non-thermal electrons. Additionally, during the impulsive phase these parameters may change dramatically. Thus, the interpretation of observed HXR foot point sources' altitudes is not straightforward and needs detailed numerical modelling of the electron precipitation process. The numerical model was calculated using the hydrodynamic 1D model with an application of the Fokker-Planck formalism for non-thermal beam precipitation. HXR data from RHESSI were used to trace chromospheric density changes during a non-thermal emission burst, in detail. We have found that the amount of mass that evaporated from the chromosphere is in good agreement with the ranges obtained from hydrodynamical modelling of a flaring loop, and from an analysis of observed emission measure in the loop top, and with specific scaling laws. Consistency between the obtained values shows that HXR images may provide an important constraint for models - a mass of plasma that evaporated due to a non-thermal electron beam depositing energy in the chromosphere. High-energy, non-thermal sources' (above 20 keV in this case) positions fit the column density changes obtained from the hydrodynamical model perfectly. Density changes seem to be less affected by the electrons' spectral index., Comment: Astronomy & Astrophysics, accepted

Aims. The Spectrometer Telescope for Imaging X-rays (STIX) on Solar Orbiter is a hard X-ray imaging spectrometer, which covers the energy range from 4 to 150 keV. STIX observes hard X-ray bremsstrahlung emissions from solar flares and therefore provides diagnostics of the hottest (⪆10 MK) flare plasma while quantifying the location, spectrum, and energy content of flare-accelerated nonthermal electrons. Methods. To accomplish this, STIX applies an indirect bigrid Fourier imaging technique using a set of tungsten grids (at pitches from 0.038 to 1 mm) in front of 32 coarsely pixelated CdTe detectors to provide information on angular scales from 7 to 180 arcsec with 1 keV energy resolution (at 6 keV). The imaging concept of STIX has intrinsically low telemetry and it is therefore well-suited to the limited resources available to the Solar Orbiter payload. To further reduce the downlinked data volume, STIX data are binned on board into 32 selectable energy bins and dynamically-adjusted time bins with a typical duration of 1 s during flares. Results. Through hard X-ray diagnostics, STIX provides critical information for understanding the acceleration of electrons at the Sun and their transport into interplanetary space and for determining the magnetic connection of Solar Orbiter back to the Sun. In this way, STIX serves to link Solar Orbiter’s remote and in-situ measurements.

The article presents a method for image analysis using asynchronous delay-tap sampling (ADTS) technique and convolutional neural networks (CNNs), allowing simultaneous monitoring of many phenomena occurring in the physical layer of the optical network. The ADTS method makes it possible to visualize the course of the optical signal in the form of characteristics (so-called phase portraits), which change their shape under the influence of phenomena (including chromatic dispersion, amplified spontaneous emission noise and other). Using the VPIphotonics software, a simulation model of the ADTS technique was built. After the simulation tests, 10 000 images were obtained, which after proper preparation were subjected to further analysis using CNN algorithms. The main goal of the study was to train a CNN to recognize the selected impairment (distortion); then to test its accuracy and estimate the impairment for the selected set of test images. The input data consisted of processed binary images in the form of two-dimensional matrices, with the position of the pixel. This article focuses on the analysis of images containing simultaneously the phenomena of chromatic dispersion and optical signal to noise ratio.

Local globality and its wanderingsIn the concept of globalization, global phenomena are large, moving, acting and locality is something small, immobile and yielding. In the cosmic perspective, both turn out to be small, entangled in relationships with the Universe and being in constant motion. The text analyzes the relationship between human locality, globality of Earth and the universality of the Universe. The conclusion is that important questions about the meaning of these connections remain open.

Caliste-SO is CdTe X-ray pixelated detector employed in STIX telescope which is one of the instruments on-board Solar Orbiter mission. In such type of detectors charge sharing between adjacent pixels is expected. The effect can affect measured spectra which requires the development of dedicated method for scientific data processing. In this article, we present simulations of the charge sharing with regard to incoming photon energy. We define two processes causing charge sharing: fluorescence and movement of charge cloud. First type was calculated using Geant4 toolkit to determine the response of the detector. Additionally we prepared dedicated software written in Interactive Data Language (IDL) to calculate instrumental effects: Fano and electronic noise, charge loss and properties of the entrance window. To calculate second type of charge sharing we calculated movement of charge cloud in the crystal using Fick’s second law. Our simulation shows that for Caliste-SO detectors charge sharing strongly depends on energy of incoming photon. The fraction of events classified as double counts is nearly 6% for 150 keV photons. Furthermore, we calculated the charge sharing for the Caliste64 detector. For this case our result is confirmed by laboratory measurements.

The Spectrometer Telescope for Imaging X-rays (STIX) is one of the instruments installed onboard Solar Orbiter mission which will be launched in February 2020. After 1.5 years of cruise phase it will start to gather scientific data from the orbit with perihelion distance about 0.28 au. It means that STIX will operate also during the next solar minimum. In the paper we estimate flux measured by the instrument during periods of low solar activity. For this purpose we used solar observations which were recorded by the Solar Photometer in X-rays (SphinX) during the last minimum of solar activity. The estimation was obtained for instruments overlapping energy range from 4 to 15 keV. Presented results indicate that STIX instrument will provide efficient imaging the solar emission even during low level of solar activity (B1 GOES class).

We present a novel X-ray assembly of functionally related instrument blocks intended to measure solar flare and active region (AR) spectra from within the Russian instrument complex KORTES, to be mounted aboard the International Space Station (ISS). SolpeX consists of three blocks: fast-rotating multiple flat crystal Bragg spectrometer, pin-hole X-ray spectral imager and Bragg polarimeter. This combination of measuring blocks will offer an opportunity to detect/measure possible X-ray polarization in soft X-ray emission lines/continuum and record spectra of solar flares, in particular during their impulsive phases. Polarized Bremsstrahlung and line emission may arise from presence of directed particle beams colliding with denser regions of flares. As a result of evaporation, the X-ray spectral-components are expected to be Doppler shifted, which will also be measured. In this paper, we present details of the construction of three SolpeX blocks and discuss their functionality. Delivery of KORTES with SolpeX to ISS is expected in 2020/2021.

We present a multiwavelength analysis of the long-duration flare observed on 15 April 2002 (soft X-ray peak time at 03:55 UT, ). This flare occurred on the disk (S15W01) in NOAA 9906 and was observed by a number of space instruments including the Extreme-Ultraviolet Imaging Telescope on the Solar and Heliospheric Observatory (SOHO/EIT), the RESIK spectrometer onboard the Coronas-F spacecraft, and the Ramaty High Energy Solar Spectroscopic Imager (RHESSI). We have performed a complex analysis of these measurements and studied the morphology and physical parameters characterizing the conditions in flaring plasmas. The 195 Å SOHO/EIT images have been used to study evolution of flaring loops. Analysis of RHESSI data provided the opportunity for a detailed analysis of hard X-ray emission with 1 keV energy resolution. We have used Geostationary Operational Environmental Satellite (GOES) observations for isothermal interpretation of the X-ray measurements. Temperature diagnostics of the flaring plasma have been carried out by means of a differential emission measure (DEM) analysis based on RESIK X-ray spectra. The DEM distributions were calculated based on two methods: Withbroe–Sylwester (WS) and differential evolution (DE). Both of the approaches provided similar results. We obtained two-component DEM distributions independent of the evolutionary flare phase. We found that the amount of energy of thermal plasma for this flare is of the order of 1030 ergs. The values obtained by assuming an isothermal plasma model are lower than those determined from the differential emission measure distributions.

In the paper experimental investigations related with analysis of navigational precision of three chosen GNSS receivers are shown. Used receivers allow for measurement of navigational signals in following modes of operations: receiving signals from single-frequency GPS system, dual-frequency GPS/GLONASS system, and receiving signals from GPS constellation with use of differential measurements. In the last mode the base station and mobile receiver were configured for transmitting/receiving differential corrections by pair of industry-grade radio modems. The most important features and configuration of navigational receivers for conducted experiment are presented. Afterward the features of computer program designed especially for simultaneous acquisition, analysis of quality parameters and archiving of navigational signals are shown. The results of conducted investigations are also shown. For each of the receivers quantity and quality parameters such as maximum and minimum numbers of visible satellites and DOP (dilution of precision) parameters achieved during the experiment are given.

In order to study the dynamics and thermal properties of two kinematic classes of coronal mass ejections (CMEs) we analyzed two well-observed events in the early stage of their propagation, using multiwavelength observations from the Atmospheric Imaging Assembly (AIA) of the Solar Dynamic Observatory (SDO). For deriving differential emission measure (DEM) profiles and DEM maps of the basic structures of CMEs, we used two methods: the regularized inversion and the iterative forward–fitting approach. For the CME associated with a M2.0 class flare (CME-FL), we identified a hot, moving, blob-like feature which seems to be a candidate for a CME flux rope. Furthermore, an expanding system of loop and coronal dimming was clearly seen in AIA images. For the CME related to an eruptive prominence (CME–EP), we observed an eruptive plasmoid and a failed-eruption of cold plasma. However, we also recognized warm and hot moving signatures that revealed a multi-temperature nature of the eruptive prominence. Our main results are as follows: (a) An analysis of the examples of the two different kinematic classes of CMEs shows that despite the slight variations in the values of speeds and accelerations (CME-FL: v ≈ 174 km s–1, a ≈ 350 ms–2; CME-EP: v ≈ 135 km s–1, a ≈ 160 ms–2) they present the same kinematic behavior; (b) in the field of view of the LASCO coronagraphs these two events have the similar, positive accelerations; (c) for both events we observed an impulsive acceleration phase (IAP); (d) the expanding structures seen in 171 A, 193 A, 211 A in both events move faster than the hotter blobs; (e) the plasmoid core for the CME-FL is hot (8.0–15.8 MK); (f) the expanding blob and the hot structure in the prominence region for the CME–EP event have the similar temperature range (0.8–2.5 MK). (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The article presents the possibilities of using the Asynchronous Delay Tap Sampling and Convolutional Neural Network methods to simultaneously monitor the impairments of Chromatic Dispersion and Optical Signal to Noise Ratio. Using the ADTS method, which allows the presentation of distortions in the form of characteristics, a set of 10,000 images was generated simultaneously disturbed by the combination of CD and OSNR impairments. Next, using the convolutional algorithms of neural networks, the network learning process was carried out (using images obtained from the ADTS method) in order to obtain the best model for recognizing the occurring impairments and predicting their values. After a large number of tests, very good results were obtained ensuring a high adjustment of the models at the level of matching ratio R 2 above 0.99 (and even above 0.999 for models for Chromatic Dispersion). Models with such a fit meet the requirements set for monitoring systems to recognize the value of occurring impairments within appropriate accuracy limits

In 2009, the Russian Complex Orbital Observations Near-Earth of Activity of the Sun (CORONAS-Photon) spacecraft was launched, carrying the Polish Solar PHotometer In X-rays (SphinX). The SphinX was most sensitive in the spectral range 1.2 – 15 keV, thus an excellent opportunity appeared for comparison with the low-energy end of Ramaty High Energy Solar Spectroscopic Imager (RHESSI) spectra. Common spectral measurements with these instruments cover the range where most of the flare energy is accumulated. We have chosen four consecutive small solar events observed on 4 July 2009 at 13:43 UT, 13:48 UT, 13:52 UT, and 13:55 UT (RHESSI flare peak times) and used them to compare the data and results from the two instruments. Moreover, we included Geostationary Operational Environmental Satellite (GOES) records in our analysis. In practice, the range of comparison performed for SphinX and RHESSI is limited roughly to 3 – 6 keV. RHESSI fluxes measured with a use of one, four, and nine detectors in the 3 – 4 keV energy band agree with SphinX measurements. However, we observed that SphinX spectral irradiances are three times higher than those of RHESSI in the 4 – 6 keV energy band. This effect contributes to the difference in obtained emission measures, but the derived temperatures of plasma components are similar. RHESSI spectra were fitted using a model with two thermal components. We have found that the RHESSI hot component is in agreement with GOES, and the RHESSI hotter component fits the SphinX flaring component well. Moreover, we calculated the so-called thermodynamic measure and the total thermal energy content in the four microflares that we studied. The results obtained show that SphinX is a very sensitive complementary observatory for RHESSI and GOES.

We propose a new model for description of solar flare lightcurve profile observed in soft X-rays. The method assumes that single-peaked ‘regular’ flares seen in lightcurves can be fitted with the elementary time profile being a convolution of Gaussian and exponential functions. More complex, multi-peaked flares can be decomposed as a sum of elementary profiles. During flare lightcurve fitting process a linear background is determined as well. In our study we allow the background shape over the event to change linearly with time. Presented approach originally was dedicated to the soft X-ray small flares recorded by Polish spectrophotometer SphinX during the phase of very deep solar minimum of activity, between 23rd and 24th Solar Cycles. However, the method can and will be used to interpret the lightcurves as obtained by the other soft X-ray broad-band spectrometers at the time of both low and higher solar activity level. In the paper we introduce the model and present examples of fits to SphinX and GOES 1-8 Å channel observations as well.

Solar flare X-ray loop top sources (LTSs) are known since early observations from Skylab.They are always present accompanying long duration events (LDE), but their nature remains unclear. One of the main unknowns is spatial structure of LTSs. Observations indicate that LTSs are large and diffuse, but several authors suggested that there is present a fine, internal structure within them which should be resolved even using present space instrumentation.We present an example for the solar flare well observed by SDO/AIA and RHESSI. The LTS was dynamic with an episode of splitting into two sources. We performed detailed analysis of X-ray sources morphology using restored RHESSI images. Moreover, we conducted a number of simulations taking into account various possible spatial distributions of X-ray emission. We have found that in case of the flare investigated RHESSI should be capable to detect the fine structure if present. However it is not visible on the restored images. Some of our simulations suggest that we can also miss large, diffuse sources in the X-ray observations which may eventually lead to misinterpretation of the observed X-ray features.

A new methodology is given to determine basic parameters of flares from their X-ray light curves. Algorithms are developed from the analysis of small X-ray flares occurring during the deep solar minimum of 2009, between Solar Cycles 23 and 24, observed by the Polish Solar Photometer in X-rays (SphinX) on the Complex Orbital Observations Near-Earth of Activity of the Sun-Photon (CORONAS-Photon) spacecraft. One is a semi-automatic flare detection procedure that gives start, peak, and end times for single (“elementary”) flare events under the assumption that the light curve is a simple convolution of a Gaussian and exponential decay functions. More complex flares with multiple peaks can generally be described by a sum of such elementary flares. Flare time profiles in the two energy ranges of SphinX (1.16 – 1.51 keV, 1.51 – 15 keV) are used to derive temperature and emission measure as a function of time during each flare. The result is a comprehensive catalogue – the SphinX Flare Catalogue – which contains 1600 flares or flare-like events and is made available for general use. The methods described here can be applied to observations made by Geosynchronous Operational Environmental Satellites (GOES), the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and other broad-band spectrometers.

Spectrometer/Telescope for Imaging X-rays (STIX) is a part of Solar Orbiter (SO) science payload. SO will be launched in October 2018, and after three years of cruise phase, it will reach orbit with perihelion distance of 0.3 a.u. STIX is a Fourier imager equipped with pairs of grids that comprise the flare hard X-ray tomograph. Similar imager types were already used in the past (eq. RHESSI, Yohkoh/HXT), but STIX will incorporate Moiré modulation and a new type of pixelized detectors with CdTe sensor. We developed a method of modeling these detectors' response matrix (DRM) using the Geant4 simulations of X-ray photons interactions with CdTe crystals. Taking into account known detector effects (Fano noise, hole tailing etc.) we modeled the resulting spectra with high accuracy. Comparison of Caliste-SO laboratory measurements of 241Am decay spectrum with our results shows a very good agreement. The modeling based on the Geant4 simulations significantly improves our understanding of detector response to X-ray photons. Developed methodology gives opportunity for detailed simulation of whole instrument response with complicated geometry and secondary radiation from cosmic ray particles taken into account. Moreover, we are developing the Geant4 simulations of aging effects which decrease detector's performance.

We present results of multitemperature analysis of GOES C7.2 class flare SOL2003-03-29T10:15. This event occurred close to the centre of the solar disk and had two maxima in soft X-rays. We have performed analysis of physical parameters characterizing evolution of conditions in the flaring plasma. The temperature diagnostics have been carried out using the differential emission measure (DEM) approach based on the soft X-ray spectra collected by RESIK Bragg spectrometer. Analysis of data obtained by RHESSI provided opportunity to estimate the volume and thus calculating the density and thermal energy content of hot flaring plasma.

It is well known that not all solar flares are connected with eruptions followed by coronal mass ejection (CME). Even strongest X-class flares may not be accompanied by eruptions or are accompanied by failed eruptions. One of important factor that prevent eruption from developing into CME is strength of the magnetic field overlying flare site. Few observations show that active regions with specific magnetic configuration may produce many CME-less solar flares. Therefore, forecasts of geoeffective events based on active region properties have to take into account probability of confining solar eruptions. Present observations of SDO/AIA give a chance for deep statistical analysis of properties of an active region which may lead to confining an eruption. We developed automated method which can recognize eruptions in AIA images. With this tool we will be able to analyze statistical properties of failed eruptions observed by AIA telescope.

It is well known that there is temporal relationship between coronal mass ejections (CMEs) and associated flares. The duration of the acceleration phase is related to the duration of the rise phase of a flare. We investigate CMEs associated with slow long duration events (LDEs), i.e. flares with the long rising phase. We determined the relationships between flares and CMEs and analyzed the CME kinematics in detail. The parameters of the flares (GOES flux, duration of the rising phase) show strong correlations with the CME parameters (velocity, acceleration during main acceleration phase and duration of the CME acceleration phase). These correlations confirm the strong relation between slow LDEs and CMEs. We also analyzed the relation between the parameters of the CMEs, i.e. a velocity, an acceleration during the main acceleration phase, a duration of the acceleration phase, and a height of a CME at the end of the acceleration phase. The CMEs associated with the slow LDEs are characterized by high velocity during the propagation phase, with the median equal 1423 km/s. In half of the analyzed cases, the main acceleration was low (a, Solar Physics, accepted

The paper presents a method for determining the pixel response using Geant4 package. The response is calculated for cadmium telluride sensor of Caliste-SO detector. Caliste-SO will be used in STIX instrument on board Solar Orbiter, which is M-class mission of the ESA’s program Cosmic Vision 2015-2025. Solar Orbiter is to be launched in October 2018. STIX instrument will provide imaging spectroscopy of solar hard X-ray emissions (4 – 150 keV) using a Fourier-imaging technique. Response of pixels in pixelized Caliste-SO detector vary between each other due to different sizes and locations. This can influence the scientific data obtained from STIX. Additionally, in the simulation we considered detector effects, like: hole tailing, damage layer, Fano and electronic noise.

We use simultaneous observations from RESIK and RHESSI instruments to compare plasma properties of a major solar flare in its rise and gradual phase. This event occurred on 2002 August 3 (peak time at 19:06 UT). The flare had a very good coverage with RESIK data and well-resolved soft and hard X-ray sources were seen in RHESSI images. Spectra of X-ray radiation from RHESSI images are studied and compared with RESIK measurements in different flare phases. Result shows large differences in flare morphology and spectra between flare rise and gradual phase.

Context. The thick-target model of the impulsive phase of solar flares describes the propagation of non-thermal electron beams into the chromosphere. The stopping depth of the electron is related to its energy. Thus, the thermal reaction at different levels should be connected to the parameters of the electron spectrum. Aims. We investigate the impulsive thermal reaction produced by non-thermal electron beams at different heights of the solar atmosphere observed in solar flare footpoints. Methods. We used methods developed for the investigation of the impulsive SXR brightenings. The EUV and UV images obtained by TRACE in the 171 A and 1600 A filter were used as the basic data set for this analysis. For the first time, EUV images have been desaturated using diffraction pattern properties. Results. We find that the thermal impulsive reaction observed in solar flare footpoints is different for UV and EUV brightenings. Results are compared to those obtained for the impulsive SXR brightenings. We find that observed dissimilarities are connected to the properties of the non-thermal electron spectrum and to the depth of their penetration into the chromosphere. Moreover, we show that the lower levels of the chromosphere are excited by more energetic electrons.

The paper presents a two methods for simulation of signal induction in the detector. First method base on carriers tracks calculation while second method include simplification of accelerating calculations. Calculation has been performed for Caliste-SO detector, which is cadmium telluride X-ray detector. This detector will be used in the Solar Orbiter/STIX instrument. Solar Orbiter is M-class mission of the ESA's programme Cosmic Vision 2015-2025, which is conducted in collaboration with NASA. It will be launched in October 2018. STIX (Spectrometer/Telescope for Imaging X-Rays) is X-ray telescope and spectrometer and will observe solar X-ray emission from 4 to 150 keV using Fourier-imaging technique. Deep space condition can influence significantly the detector parameters. Tools for detectors behaviour analysis are needed to understand how this harsh radiation environment can influence detector quantum efficiency.

Footpoints of several strong solar flares have been investigated using images obtained by Ramaty High Energy Solar Spectroscopic Imager ( RHESSI ). The altitude of hard X-ray sources in various energy bands has been measured. Some observational characteristics of the energy-height relation have been obtained and presented in the form of histograms. Using them we were able to conclude that during impulsive phase the region in which electrons are stopped is rather narrow with the thickness in the range 1500–4000 km. Moreover, it is shown that all electrons producing photons with energies exceeding 20–30 keV are stopped at similar altitudes. For the flare of 3 August 2002 we analysed the temporal evolution of the energy-height relation. It has been shown that changes in this relation can be interpreted as a manifestation of simultaneous upflows and downflows of the transition region and chromosphere. Obtained values of velocities are between −50 and 150 km/s.