Solar Type Research Articles

Publisher Correction: Fine structures of a solar type III radio bursts observed with LOFAR

Publisher Correction: Fine structures of a solar type III radio bursts observed with LOFAR

A type II radio burst associated with solar filament–filament interaction

Aims. Solar radio type II bursts are often associated with coronal shocks driven by solar eruptions. In this study, we report a type II burst associated with filament–filament interaction. Methods. Combining the high-quality multiwavelength observations from CHASE, SDO, STEREO, and CALLISTO, we conducted a detailed study of the type II burst associated with filament–filament interaction. Results. On 2023 September 11, an erupting filament (F1) likely disturbed a nearby long filament (F2), causing F2 to subsequently erupt. As a result of possible magnetic reconnection between ejective materials from the two filaments, loop-like structures formed perpendicular to them. Subsequently, the expansion of these loop-like structures triggered a strong coronal mass ejection (CME). Interestingly, a type II burst appeared on the solar spectrum around the time when the loop-like structures formed and the CME appeared above the occulting disk of STEREO/COR1. By converting the frequency of the type II burst to the coronal height using polarization brightness data recorded by the COR1 coronagraph and the spherically symmetric polynomial approximation technique, we determined the formation height of the type II burst to be around 1.45 R⊙, with a speed of approximately 440 km s−1. This is comparable to the observed height of the CME (∼1.43 R⊙), although slightly lower in speed (540 km s−1). Conclusions. All these results indicate that the type II burst was closely associated with filament–filament interactions and was possibly excited by the accompanying CME at the flank. We suggest that the filament–filament interactions played an important role in producing the type II burst by acting as a piston to trigger a strong CME.

Experimental investigation of nickel-based nanofluid on the performance of evacuated tube solar collector

This paper conducts an experimental investigation of an evacuated tube solar collector type solar collector employing a unique Ni/water nanofluid to assess its exergetic and energy performance. The investigation sheds light on the intricate behavior of nanofluid and their consequential impact on the efficiency, thermal properties, and entropy generation within the framework of evacuated tube solar collector (ETSC). The study reveals that an escalation of nickel nanoparticles volumetric concentration results in a reduction of specific heat capacity, attributed in part to the clustering effect of nanoparticles mixed with working fluid. Nevertheless, higher temperatures counterintuitively lead to an augmentation in specific heat capacity. The study presents the comparative behavior of nanofluid and the parent base fluid. The study further elucidates that augmenting the volumetric concentration of nanoparticles causes a reduction in the temperature difference between the collector's both side inlet and outlet, affecting thermal efficiency positively. Moreover, with mass flow rate contribute and increased volumetric concentration to a diminished outlet temperature, thereby enhancing the efficiency of ETSC. The study also analyzed the thermophysical properties such as thermal conductivity, viscosity, and specific heat of the Ni/water nanofluid across different volumetric concentrations and temperature ranges from 25 °C to 50 °C. Furthermore, the thermal performance of the collector was evaluated at various mass flow rates ranging from 0.0085 kg/s to 0.051 kg/s. The findings revealed a maximum energy efficiency of 73.14% at a volumetric concentration of 1% and a mass flow rate of 0.041 kg/s.

Noble Gases, Carbon and Nitrogen Isotopes in Different Lithologies of Pesyanoe: Irradiation History and Impact Processes on the Aubrite Parent Body

Abstract We present the results of stepwise crushing and combustion analyses for noble gases, carbon and nitrogen in Pesyanoe aubrite pyroxene lithologies, composed of grey (Px-G) and light (Px-B) enstatites differing in the degree of impact processing and the number of inclusions. Our study identifies three main noble gas endmembers in Pesyanoe: a cosmogenic component, radiogenic 40Ar, and an endmember representing a mixture of solar wind and Q components in variable proportions. Based on petrographic and noble gas data we argue that these gases accumulated in the material during its regolith history and were later redistributed into gas inclusions/voids as the result of an impact event. During impact metamorphism, Px-G acquired its grey color and multiple gas inclusions were formed within it, more than in case of Px-B. Our study demonstrates for the first time: (1) The host phase of gases trapped during shock metamorphism are grains of rock-forming minerals, in particular Px-G, due to the formation of a large number of cracks in the direction of cleavage during brittle deformation, (2) The gas capture is associated not with the final stage of the formation of consolidated fragmental breccia, at which lithification of the fragments occurred, but with one of the intermediate impact events. High amounts of trapped and cosmogenic noble gases are released during the stepwise crushing—significantly higher than in case of any other studied aubrite. Some unusually high 36Ar/132Xe ratios (up to 54 780 versus 22 705 in the solar wind) were discovered during crushing of Px-G. Our preferable explanation of this phenomenon is a specific superposition of noble gas elemental fractionation processes related to the impact cratering of the Pesyanoe parent body. The carbon isotopic composition (δ13C = –21.2 ± 0.2‰, 1σ) is slightly heavier than that of the Bustee aubrite carbon. The combined use of different extraction methods made it possible to determine that the solar type and indigenous (δ15Nindig = –0.1 ± 3.2‰, 1σ) nitrogen components are located in the gas inclusions, whereas the extraneous nitrogen component (~+45‰) is chemically bound. The large cosmic ray exposure age variations (44 and 55 Ma in case of Px-G and Px-B, respectively) and the heterogeneous distribution of solar-type gases in Pesyanoe aubrite point to a diverse irradiation history of the material before breccia formation. Alternatively/additionally, cosmogenic gases (as well as solar and primordial) in Px-G may have became lost and/or partly redistributed into gas inclusions as a result of the impact event.

Observation of an Extraordinary Type V Solar Radio Burst: Nonlinear Evolution of the Electron Two-Stream Instability

Solar type V radio bursts are associated with type III bursts. Several processes have been proposed to interpret the association, electron distribution, and emission. We present the observation of a unique type V event observed by e-CALLISTO on 7 May 2021. The type V radio emission follows a group of U bursts. Unlike the unpolarized U bursts, the type V burst is circularly polarized, leaving room for a different emission process. Its starting edge drifts to higher frequency four times slower than the descending branch of the associated U burst. The type V processes seem to be ruled by electrons of lower energy. The observations conform to a coherent scenario where a dense electron beam drives the two-stream instability (causing type III emission) and, in the nonlinear stage, becomes unstable to another instability, previously known as the electron firehose instability (EFI). The secondary instability scatters some beam electrons into velocities perpendicular to the magnetic field and produces, after particle loss, a trapped distribution prone to electron cyclotron masering (ECM). A reduction in beaming and the formation of an isotropic halo are predicted for electron beams continuing to interplanetary space, possibly observable by Parker Solar Probe and Solar Orbiter.

Peningkatan teknologi bagi agroindustri pliek-u sebagai upaya pelestarian kearifan lokal di Aceh [Technology improvement on pliek-u agroindustry as an effort to maintain a local wisdom in Aceh

Pliek-u is a specialty food product in Aceh with local wisdom values that should be preserved. The Program of Community Service Based Product (PKMBP) aimed to improve the pliek-u agro-industry by adapting simple processing technologies so that it could lighten work, produce quality products, and attract the interest of the younger generation as pliek-u entrepreneurs in future. The method applied consist of surveys, preparation of tools and materials, assembly of a solar tunnel dryer type Hohenheim Aceh and a hydraulic press, training and dissemination of technology through field schools, and evaluation of the program with pre-tests and post-tests. Data analysis was carried out using the Wilcoxon rank test with alpha of 5%. The results of the program were the construction of 1 unit of Hohenheim Aceh tunnel dryer, 1 unit of hydraulic press, and the implementation of training and dissemination activities which have been published in the form of videos on YouTube media and press releases through online media. The results of the Wilcoxon rank test also showed that of the 13 participants whose data were valid, 100% of participants received positive rankings and the pre-test scores were significantly different from the post-test scores. Thus, it can be concluded that the program carried out has contributed to increasing the knowledge, expertise capacity, and interest of participants in pliek-u processing technologies since the profile of conventional agroindustry can be transformed to be better agroindustry by the use of solar tunnel dryer type Hohenheim Aceh and hydraulic press. In addition, the use of technologies will ensure the halal requirement of pliek-u.

"Is it Possible that the Connection Between Solar Lentigines and Type 2 Diabetes Mellitus Can Result from a Common Cause – Solar Alpha Particle Streams?"

"Is it Possible that the Connection Between Solar Lentigines and Type 2 Diabetes Mellitus Can Result from a Common Cause – Solar Alpha Particle Streams?"

On the industrial solar drying of tomatoes in Biskra : A preliminary study

The objective of this study is to carry out a pre-feasibility study of solar industrial drying as a preliminary step before investing in large-scale solar drying projects in Algeria. Our primary goal is to promote the use of industrial solar dryers and to incite public authorities and industrials to invest in this promising niche. This work aims to strengthen the contribution of renewable energies and particularly solar energy in the sustainable development of the agri-food sector. Indeed, using solar energy will reduce the energy consumption and decrease greenhouse gas emissions of drying process. The prefeasibility analysis is achieved using the RETScreen Suite. Our study aims to investigate energy consumption of an industrial solar dryer of tomatoes, located in the city of Biskra. Various parameters as solar collector type and drying air temperature were tested and discussed. The obtained results showed a reduction in energy consumption up to 35%. Likewise, the reduction of GHG emissions recorded very favorable rates. This study's findings provide a preliminary vision for investors in the agri-food sector to build their project so they may maximize their profit while supporting the environment by lowering carbon emissions.

Weaknesses of steady state analysis when used for selecting solar air heaters

The paper highlights the constrains faced by the user when choosing the most appropriate solar collector from a set of collectors belonging to the same category. Two basic kinds of one porous and one non-porous with single flow/pass flat solar air heaters were tested. The collectors have the same size but different internal shapes and absorber materials. The two collectors were tested and a shading procedure was implemented in order to emphasize several aspects related to the thermal inertia of the collectors. Comparison has been made between the efficiency values obtained experimentally. The shade test shows a faster decrease of the outlet air temperature for V-porous absorber collector in comparison with the U-corrugated absorber collector i.e. 6 °C and –3.5 °C respectively in a time interval of 74 s. Exposing the collectors on a fresh heating cycle under a low stability radiative regime (450–750 W/m2) one observe that 60% of the first 180 s the corrugated collector outperforms the porous collector; after that interval of time the porous collector becomes more effective. The low thermal inertia of the solar air collectors yields high variation of the thermal efficiency in days with low stability of the radiative regime. In such days, using measured series of solar irradiance data with long sampling period between two successive measurements does not allow a proper choice of the most appropriate solar collector type.

Burst-classifier: Automated classification of solar radio burst type II, III and IV for CALLISTO spectra using physical properties during maximum of solar cycle 24

Continuous observation of solar radio bursts (SRBs) throughout the year using the CALLISTO spectrometer generates a huge volume of spectral data. This study introduces a burst-classifier algorithm, which is an automated algorithm, to classify the SRB spectrum into three solar radio bursts, namely Type II (SRBT II), Type III (SRBT III) and Type IV (SRBT IV). The proposed algorithm was designed using four characteristic parameters derived from a collection of training dataset files. The characteristic parameters were derived from the intensity bursts observed on frequency channels and timesteps of the spectrum. This dataset consisted of 50 spectra of SRBT II and SRBT III, along with 40 spectra for SRBT IV, collected during the solar maximum of 2014 (Solar Cycle 24). After observations and analysis of the training dataset, each burst type was set up with a threshold. A training dataset of 80 data spectra from 2013 to 2016 was used to test the algorithm. Accuracy of the proposed algorithm was calculated using the percentage of true positives (TP) and false positives (FP). Findings demonstrate an accuracy of ∼74 % with 57 out of 80 spectra classified as TP and 23 spectra as FP.

Spectral cleaving in solar type II radio bursts: Observations and interpretation

Context. Shock waves in the solar corona are associated with solar flares and coronal mass ejections (CMEs). Type II solar bursts are radio signatures of shock waves in the solar corona. They are driven by solar flares or CMEs. Despite extensive studies, the intricate spectral patterns observed in type II solar bursts occasionally pose new challenges for the theory of electron acceleration in shocks. Aims. We study a newly identified feature in type II solar bursts called spectral cleaving. This feature is characterized by the actual branching of a type II radio emission lane in radio spectral data. Methods. We analyzed the type II burst exhibiting spectral cleaving in high-fidelity dynamic spectra obtained using the URAN-2 radio telescope (8.25–33 MHz; Poltava region, Ukraine) on 2011 February 14. The high-resolution spectrograms were examined to ascertain its spectral morphology. Results. Our research represents the first recognition of spectral cleaving as a peculiarity of type II bursts that is yet to be classified. This effect occurs due to the shift (or migration) of radio source(s) along a shock front, which in turn is caused by changes in the magnetic field orientation ahead of the propagating shock front. Conclusions. The spectral cleaving observed in solar type II bursts reveals a distinct phenomenon that indicates complex interactions between shock waves and magnetic fields in the solar corona. This discovery enhances our understanding of the mechanisms behind solar radio emissions and emphasizes the need for further observational studies to verify these findings.

A novel multi-objective decision-making model to determine optimum resource and capacity configuration for hybrid electricity generation systems: A comparative case study in Türkiye

The rapid depletion of fossil fuels, their negative environmental impacts due to harmful carbon emissions, and the drawbacks of the sole use of intermittent renewable energy resources on system reliability necessitate the use of more advanced energy system technologies. As a result, hybrid electricity generation systems offer an innovative alternative to conventional energy systems. However, the technical complexity and variability of these systems require the application of multi-objective optimization techniques to determine the optimal sizing and system design. Therefore, in this study, we suggest a multi-objective decision-making (MODM) model that involves five conflicting objectives to find the optimal resource configuration and auxiliary source capacity allocation within the framework of the multi-source electricity production method in Türkiye. The MODM model aims to maximize the utilization of resource potentials and the jobs created, while simultaneously minimizing the levelized cost of energy (LCOE), construction duration, and carbon emissions. The MODM model was solved using fmincon and fgoalattain multi-objective optimization algorithms using the Goal Attainment Method in MATLAB and the model results were subsequently compared to the real-world data. According to the model results, the optimal capacity to be allocated for the auxiliary source units is 13,749.58 MWm, while the capacity allocated according to the real-world data as of March 2024 is 2495.49 MWm. In contrast to the model's prediction of 90.8 % solar-based auxiliary unit installations, 99.8 % of auxiliary units are based on solar PV in the actual case. Furthermore, hydro or geothermal-based auxiliary sources are not allocated any capacity, which is consistent with the actual situation. The capacity allocated for the wind (primary source) + solar (auxiliary source) configuration is 76.2 %, whereas in reality, it accounts for 65.6 % of the total installations. Consequently, the model findings suggest that the maximum capacity allocation is for the wind (primary source) + solar (auxiliary source) type hybrid electricity generation system.

Differential Rotation of CoRoT Stars and a Kepler Binary Star from Starspot Transit Mapping

Abstract While direct magnetic field measurements are rare for slowly rotating stars, spots observed during planetary transits provide a potential indicator of magnetic activity on stellar surfaces. Moreover, the rotation of the stellar surface can be probed by monitoring the spots’ position with time in subsequent transits. This study investigates the dynamic interplay of rotational shear and stellar rotation rate in six stars of spectral types F to M, all hosting exoplanets observed by the CoRoT space mission, except for one binary star from Kepler. The analysis, facilitated by the ECLIPSE code, unveils the physical properties of stellar spots, including radius, intensity, temperature, and position. The five CoRoT stars exhibit spot characteristics consistent with those observed in solar type stars. The determination of a spot longitude during different transits allows for the inference of the star’s differential rotation profile, revealing a decreasing trend of rotational shear with the mean stellar rotation period, given by Δ Ω ∝ P ¯ − 0.9 . This implies that, at least for slow rotators (mean rotation period >5 days), as stars age, their differential rotation decreases. Additionally, the six stars analyzed here seem to fall into two categories, according to their spot flux deficit: those with ΔF spot > 0.005 and those with ΔF spot < 0.002.

Time Profile Study of Type III Solar Radio Bursts Using Parker Solar Probe

Solar type III radio bursts are crucial indicators of energetic electron activity in the solar corona and interplanetary space. Our assessment of 43 interplanetary type III bursts, recorded by the FIELDS instrument on board the Parker Solar Probe during Encounters 05 to 11, has led to significant and complex findings. We have analyzed time profile features across a frequency range of 19–0.5 MHz, revealing dependencies on frequency and providing insights into duration, burst speeds, bandwidths, and drift rates. This novel analysis has unveiled a spectral index of −0.63 ± 0.04 for rise, −0.69 ± 0.03 for decay time, and −0.68 ± 0.03 for the total duration. We have determined the average electron beam velocities for front, middle, and back as 0.15c, 0.13c, and 0.08c, respectively. Our findings show that faster electron beams generate emissions with shorter duration. The average ratio of the front-to-back velocity is 1.87, and the ratio of front-to-middle velocity is 1.23. We have also discovered a strong relationship between burst duration with rise, peak, and decay times, particularly pronounced with decay time (correlation coefficient = 0.95). This indicates that the entire temporal profile, including rise, peak, and decay phases, collectively contributes to event duration and is not solely influenced by external factors like plasma conditions or electron beam dynamics but also by internal burst processes. These complex findings shed light on the physical mechanisms governing burst dynamics, revealing intricate interactions between electron beam characteristics and observed temporal and spectral traits of type III solar radio bursts.

Fine structures of a solar type III radio bursts observed with LOFAR

Fine structures of a solar type III radio bursts observed with LOFAR

Low-frequency solar radio type II bursts and their association with space weather events during the ascending phase of solar cycle 25

Abstract. Type II solar radio bursts are signatures of the coronal shocks and, therefore, particle acceleration events in the solar atmosphere and interplanetary space. Type II bursts can serve as a proxy to provide early warnings of incoming solar storm disturbances, such as geomagnetic storms and radiation storms, which may further lead to ionospheric effects. In this article, we report the first observation of 32 type II bursts by measuring various plasma parameters that occurred between May 2021 and December 2022 in solar cycle 25. We further evaluated their accompanying space weather events in terms of ionospheric total electron content (TEC) enhancement using the rate of TEC index (ROTI). In this study, we find that at heliocentric distance ∼1–2 R⊙, the shock and the Alfvén speeds are in the range 504–1282 and 368–826 km−1, respectively. The Alfvén Mach number is of the order of 1.2≤MA≤1.8 at the above-mentioned heliocentric distance. In addition, the measured magnetic field strength is consistent with the earlier reports and follows a single power law B(r)=6.07r-3.96G. Based on the current analysis, it is found that 19 out of 32 type II bursts are associated with immediate space weather events in terms of radio blackouts and polar cap absorption events, making them strong indications of space weather disruption. The ROTI enhancements, which indicate ionospheric irregularities, strongly correlate with GOES X-ray flares, which are associated with the type II radio bursts recorded. The diurnal variability in ROTI is proportional to the strength of the associated flare class, and the corresponding longitudinal variation is attributed to the difference in longitude. This article demonstrates that since type II bursts are connected to space weather hazards, understanding various physical parameters of type II bursts helps to predict and forecast the space weather.

Evaluation of Constructive Parameters to Minimize the Effects of Solar Radiation in Households with Tropical Climate

In tropical climates, the energy consumption of buildings is strongly influenced by solar radiation. However, more research needs to be done on how specific design parameters can mitigate the effects of solar radiation in tropical homes. This study uses simulations in EnergyPlus to evaluate how orientation, roof solar absorptance, overhang depth, glass type, and wall type affect energy consumption in a typical middle-income home in a tropical climate. The results highlight the benefits of adequate solar absorbance and correct orientation. Incorporating insulation into exterior walls does not offer significant improvements in the energy performance of the building. Key words. Building energy simulation, Tropical climate, parametric analysis.

تقييم أداء أنظمة ري مختلفة تعمل بالطاقة الشمسية وتأثيرها على إنتاجية الباقلاء (Vicia Faba…L)

An experiment was carried out at Al-Raed Research Station, which is located on the Baghdad-Anbar Road. It was conducted during the winter season of 2022-2023, in order to evaluate the performance of different solar irrigation systems and their effect on bean yield (Vicia faba… L). A randomized complete block design (RCBD) was used with three replications. The experiment consists of three factors. first factor was the solar panel type with two levels: mono-crystalline and poly-crystalline. Second factor was the irrigation system with two levels: drip and sprinkler irrigation system. The third factor was the distances between the sub-lines with three levels (40, 60, 80 cm). The results show that the monocrystalline achieved the best result by achieving the highest irrigation system efficiency (76.31%), and highest seeds yield total (6618 Kg/ha) with minimum operational costs (0.0252 $/KWh). The drip irrigation had the highest irrigation system efficiency (84.40%), and highest total seeds yield (6077 Kg/ha) with minimum operational costs (0.0340 $/ KWh). The distance (40cm) between the sublines had the highest irrigation system efficiency (76.83 %), with less operational costs (0.0398 $ / KWh).

Evaporative photovoltaic cooling - A comparison of hydraulic and air atomizing nozzles in laboratory and field measurements

Solar radiation allows the operation of photovoltaic modules, but concurrently limits the maximum power output achievable in real operation due to increasing cell temperatures. In this work, experiments are conducted to validate the functionality of an evaporative cooling system for photovoltaics by comparing the results of a custom-made mobile photovoltaic test rig with Pt100 sensors embedded into the solar cell laminate under Western European summer conditions and of a laboratory panel heater test rig. Additionally, results of an air atomizing nozzle installed in the cooling system are presented and compared to hydraulic atomizing nozzles. The cell temperature drops by a maximum of 29.3 °C with a consumption of 6.3 lh∙m2 water and 8800 lh∙m2 compressed air. Dependent on the solar cell type, the electrical efficiency increases by 8.8% – 14.5%. The comparison shows that the air atomizing nozzle yields superior results but is not cost-efficient in the application due to the cost of compressed air.

The quality of pliek-u processed by using adaptive technologies

Abstract This study aimed to evaluate the quality of pliek-u processed by using adaptive technologies namely a solar tunnel dryer type Hohenheim Aceh for drying pliek-u and a hydraulic press for separating the pliek oil from pliek-u. About 100 coconuts were grated and fermented for 9days, then dried by using a solar tunnel dryer type Hohenheim Aceh and pressed by the hydraulic press. Parameters observed were moisture, total acidity, acidity, fat content, ash content, and yield. An organoleptic test was also conduct on 30 consumers. Results showed that the moisture of pliek-u ranged from 8.61 to 12.29%. The total acidity and pH-value of pliek-u were 0.52% and 5.5, respectively. Pliek-u has fat content about 43.65% and ash content approximately 5.3%, while the yield of pliek-u was 31.33%. The consumer test showed that the average preferences score of pliek-u for all sensory properties were 4 (like). In conclusion, the quality of pliek-u processed by using adaptive technologies were good as it was processed conventionally. Moreover, some quality properties such as pH-value and fat content can be improved so that the shelf-life of pliek-u could be extended.