Showing papers on "Solar eclipse published in 2023"
TL;DR: In this paper , the authors show that the Allais eclipse effect causes the major part of the growth of the length scale for the entire solar system and that the change in the Earth's rotation is caused by a repulsive gravitational interaction during solar eclipse.
Abstract: In addition to the Pioneer anomaly and the Earth flyby anomaly for spacecraft, other unexplained anomalies disrupt the solar system dynamics, like the astronomical unit. We show in this paper that the Allais eclipse effect causes the major part of the growth of the length scale for the entire solar system. It is the rough disturbance on the barycenter Earth- Moon implying the Sun that was recorded in the movement of the paraconical pendulum. Earth and Moon revolve around their common center of gravity, which in turn orbits the Sun, and the perturbation of the eclipse hits this double, coupled Kepler's movements. The thesis of the tidal friction supports that oceanic tidal friction transfers the angular momentum of the Earth to the Moon, slows down the rotation of the Earth while taking away the Moon. However, we think that there are not enough shallow seas to sanction this interpretation. The Earth-Moon tidal system might be inaccurate or unreliable in determining the Earth's actual rotational spin-down rate. Our assertion is that the change in the Earth's rotation is caused by a repulsive gravitational interaction during solar eclipse. The perturbation would submit to variations and distortions the region of the barycenter of the Earth-Moon system which revolves around the Sun, with the dual secular effects that the Moon spirals outwards and that the Earth-Moon system goes away from the Sun.
5 citations
TL;DR: In this paper , the authors analyzed the dense total electron content (TEC) observations from the ground-based Global Navigation Satellite System receivers over East and South Asia to examine the development of the irregularities in the nighttime on the day of the 21 June 2020 annular solar eclipse.
Abstract: Solar eclipse is a daytime phenomenon that significantly disturbs the ionosphere, but whether the eclipse induces ionospheric irregularities in the nighttime remains unknown. In this study, we analyzed the dense total electron content (TEC) observations from the ground-based Global Navigation Satellite System receivers over East and South Asia to examine the development of the irregularities in the nighttime on the day of the 21 June 2020 annular solar eclipse. The rate of TEC index (period <5 min) indicates the occurrence of the irregularities that evolve from the large or coarse structures with a period ranging from hours to dozens of minutes in the nighttime due to the eclipse. We take advantage of the data-adaptive analysis method, Hilbert-Huang transform, to derive the instantaneous amplitude and frequency of the TEC time series, which exposes the temporal and spatial evolutions of the irregularities from larger structures continuously.
2 citations
1 citations
TL;DR: In this paper , the authors analyzed four records of questionable authenticity of total solar eclipses between the fourth and sixth centuries CE in Byzantine narrative sources and revealed the problems with and questions around the reliability of all these records from astronomical perspectives based on the latest ΔT spline curve.
Abstract: This study analysed four records of questionable authenticity of total solar eclipses between the fourth and sixth centuries CE in Byzantine narrative sources. As it has been difficult to evaluate their credibility, they have not been utilised in modern astronomical studies. Three records originated in the fourth century, all of which have problems with accurate dating and provenance. The one remaining record concerns the total solar eclipse on 512 June 29. This study first reveals the problems with and questions around the reliability of all these records from astronomical perspectives based on the latest ΔT spline curve and recently proposed ΔT constraints. It then explores their philological and historical contexts to understand how and why these records were written.
TL;DR: A correction has been made to the section 3 Results, “3.4 ISR of Jicamarca”, first paragraph, page 9. The corrected sentence is as follows: “However, the general ionospheric trends are well represented in this figure, allowing us a direct comparison to the predicted values (bottom row) as mentioned in this paper .
Abstract: Due to a production error, the words “us a” were erroneously changed to “United States of America”. A correction has been made to the section 3 Results, “3.4 ISR of Jicamarca”, first paragraph, page 9. The corrected sentence is as follows: “However, the general ionospheric trends are well represented in this figure, allowing us a direct comparison to the predicted values (bottom row)”. The publisher apologizes for this mistake. The original version of this article has been updated. OPEN ACCESS
01 Jan 2023
22 Feb 2023
TL;DR: In this article , the authors proposed a total solar eclipse Earth-based mission for ground, airborne and seaborne observations of the corona during totality for the next decade starting in 2024, which capitalizes on the unique diagnostic potential of the V+NIR coronal emission lines for the inference of key plasma parameters over a distance range of at least 5 Rs from the solar surface.
Abstract: There has been an unfortunate gap in coronal emission line observations from space in the visible and near IR (V+NIR). Their distinct scientific advantage stems from the dominance of radiative excitation in their formation, whereby their emission can be detected out to several solar radii above the limb. V+NIR emission lines can thus yield the only inferences of the physical properties of the coronal plasma, such as species temperatures, densities, elemental abundances, and speeds along and perpendicular to the line of sight in this critical spatial span. These diagnostics have been demonstrated with decades of unsurpassed high-resolution imaging and spectroscopic observations during total solar eclipses. This white paper calls for dedicated funding for a Total Solar Eclipse Earth-Based Mission for ground, airborne and seaborne observations of the corona during totality for the next decade starting in 2024. The proposed Mission capitalizes on the unique diagnostic potential offered by the V+NIR coronal emission lines for the inference of key plasma parameters over a distance range of at least 5 Rs from the solar surface. This critical coronal space is currently missing from existing and to-be launched coronagraphic instrumentation in the proposed time frame. Multi-site observing platforms for each eclipse would further capture the temporal variability of coronal plasmas over a time span of at least 1 hour, with a temporal resolution of a fraction of a minute. Furthermore, this Mission offers unsurpassed opportunities for the exploration of new technologies for future implementation with coronagraphs. This Mission has a unique significant broader impact for outreach opportunities to engage the public and the younger generations in heliospheric science from an awe-inspiring cosmic event.
TL;DR: In this article , a very low frequency (VLF) detection system has been installed in Suizhou, China, a location with the longitude almost identical to that of the NWC transmitter in Australia.
Abstract: To monitor the Very-Low-Frequency (VLF) environment, a VLF detection system has been installed in Suizhou, China, a location with the longitude almost identical to that of the NWC transmitter in Australia. In the years 2019 and 2020, two solar eclipses crossed the NWC–Suizhou path at different locations. Each solar eclipse event represents a naturally occurring controlled experiment, but these two events are unique in that similar levels of electron density variation occurred at different locations along the VLF propagation path. Therefore, we conducted a comparative study using the VLF measurements during these two eclipses. Previous studies mostly estimated a pair of the reflection height (h′) and sharpness parameter (β) using the Long Wavelength Propagation Capability code, whereas, in this study, we use the VLF amplitude and phase as constraints in order to find the electron density change that best explains the VLF measurements. The eclipse measurements could be best explained if the path-averaged β value was 0.56 and 0.62 km−1 for the 2019 and 2020 eclipse, respectively. The VLF reflection height increased from 71.5 to 73.3 km for the 2019 eclipse and from 71.1 to 72.8 km for the 2020 eclipse. The best-fit β values were consistent with the Faraday International Reference Ionosphere model and statistical studies, and the h′ change was also consistent with previous studies and theoretical calculations. Moreover, present results suggested that VLF signals collected by a single receiver were not sensitive to where the electron density change occurs along the propagation path but reflected the average path condition. Therefore, a network of VLF receivers is required in order to monitor in real time the spatial extent of the space weather events that disturb the lower ionosphere.
TL;DR: This article focused on British solar eclipse expeditions in 1889 and 1919 to highlight ways in which contributions of women and of people in colonized lands have been underrecognized by the expeditioners and in subsequent narratives about them.
Abstract: Solar eclipse expeditions in the nineteenth and early twentieth centuries led to new scientific knowledge that is often credited to prominent male scientists such as Einstein and Eddington. Results generated by named individuals nonetheless depended on the collective effort of scientific administrators, government functionaries, manual labourers, domestic assistants, naval crew members and others. Much substantive work, essential to the success of the scientific ventures, was often done by people local to the observing stations. This paper focuses on British solar eclipse expeditions in 1889 and 1919 to highlight ways in which contributions of women and of people in colonized lands have been underrecognized by the expeditioners and in subsequent narratives about them.
29 Mar 2023
TL;DR: In this paper , electron density maps derived from images acquired during the total solar eclipse of 2017 August 21 are employed to demonstrate a new technique to measure coronal magnetic fields, based on a semi-empirical formula relating the plasma magnetic energy density to the gravitational potential energy.
Abstract: The coronal magnetic field, despite its overwhelming importance to the physics and dynamics of the corona, has only rarely been measured. Here, electron density maps derived from images acquired during the total solar eclipse of 2017 August 21 are employed to demonstrate a new technique to measure coronal magnetic fields. The strength of the coronal magnetic fields is derived with a semiempirical formula relating the plasma magnetic energy density to the gravitational potential energy. The resulting values are compared with those provided by more advanced coronal field reconstruction methods based on MHD simulations of the whole corona starting from photospheric field measurements, finding very good agreement. Other parameters such as the plasma β and Alfvén velocity are also derived and compared with those of MHD simulations. Moreover, the plane-of-sky (POS) orientation of the coronal magnetic fields is derived from the observed inclination of the coronal features in filtered images, also finding close agreement with magnetic field reconstructions. Hence, this work demonstrates for the first time that the 2D distribution of coronal electron densities measured during total solar eclipses is sufficient to provide coronal magnetic field strengths and inclinations projected on the POS. These are among the main missing pieces of information that have limited so far our understanding of physical phenomena going on in the solar corona.
03 Feb 2023
TL;DR: In this article , a 3-channel spectrometer was used for diagnostics of the low solar corona in the presence of a bright helmet streamer, and the results showed that Fe X and XI lines are dominant through 0.3 R⊙, with Fe XIV maintaining a stronger signal at higher elevations.
Abstract: Abstract Spectroscopic measurements of the low solar corona are crucial to understanding the mechanisms that heat the corona and accelerate the solar wind, yet the lowest solar radii (R⊙) of the corona is difficult to observe. Our expedition collected narrow wavelengths of visible light at 530.3, 637.4, and 789.2 nm emitted by Fe XIV, X, and XI ions, respectively, from the total solar eclipse on 2019 July 2 at 20:40 UTC in Rodeo, Argentina with a bespoke 3-channel spectrometer. This paper describes the instrument, and data calibration method that enables diagnostics out to ≈1.0 R⊙ above the solar limb within a bright helmet streamer. We find that Fe X and XI lines are dominant through 0.3 R⊙, with Fe XIV maintaining a stronger signal at higher elevations. Thermal broadening is consistent with 4 MK for the cooler Fe X and XI lines, and 6 MK for the hottest Fe XIV line, which can be interpreted as differing density scale heights within isolated, isothermal flux tubes. The Doppler measurements correspond to bulk plasma motion ranging from -12 to +2.5 km s-1, with Fe XIV moving at nearly an assumed solid body rotation rate throughout 1.0 R⊙. After considering coronal rotation, these measurements are likely associated with plasma motion along the dominant longitudinal orientation of the magnetic field at the streamer base within 0.4R⊙. These results show that high resolution spectroscopy of visible light offers valuable diagnostics of the low corona, and lend insight into the interconnected loop complexity within helmet streamers.
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TL;DR: In 2019 and 2020, field research campaigns collected hourly atmospheric profiles via radiosonde surrounding the 2 July 2019 and 14 December 2020 total solar eclipses over South America from locations within the paths of eclipse totality as discussed by the authors .
Abstract: Abstract. Field research campaigns in 2019 and 2020 collected hourly atmospheric profiles via radiosonde surrounding the 2 July 2019 and 14 December 2020 total solar eclipses over South America from locations within the paths of eclipse totality. As part of these atmospheric data collection campaigns, the eclipse module of the Advanced Research Weather Research & Forecast (WRF-ARW) model was utilized to model meteorological conditions before, during, and after the eclipse events. The surface and upper air measurements collected through these campaigns have enabled further assessment and validation of the WRF-ARW eclipse module’s performance in simulating atmospheric responses to total solar eclipses. We provide here descriptions of both field campaigns and present results from comparisons of meteorological variables both at the surface and aloft using observational datasets obtained through the campaigns. The paper concludes by recommending further scientific analyses to be explored utilizing the unique datasets presented.
TL;DR: In this article , the effects in the geomagnetic field variations and ionospheric plasma density modifications caused by the total solar eclipse that occurred on 14 December 2020 over the South American sector were discussed.
Abstract: We discuss the effects in the geomagnetic field variations and ionospheric plasma density modifications caused by the Total Solar Eclipse that occurred on 14 December 2020 over the South American sector. We used ground-based magnetometer data and the Total Electron Content maps derived from the Global Navigation Satellite System to evaluate these changes. The results show that the geomagnetic field daily variation weakens between the first and last solar eclipse penumbra contact. Additionally, we observed a significant reduction of about 52.33 nT on the Equatorial Electrojet strength at Jicamarca (11.95°S, 76.88°W), where the solar obscuration reached 16.67% approximately. This behavior indicates that the solar eclipse in the equatorial region has possibly affected electric conductivities, altering the E region dynamo electric field. Consequently, it weakens the equatorial plasma fountain, affecting the Equatorial Ionization Anomaly development. Additionally, the ionospheric dynamics variations over Jicamarca during the solar eclipse event are analyzed using ionosonde data. We observe that the solar eclipse also caused a modification in the sporadic E layer and F region dynamics, indicating possible evidence of the gravity wave occurrence. Therefore, the results found here provide a better understanding of how the solar eclipse passage in the equatorial region affects the electron density in the low-latitude regions.
24 Apr 2023
24 Apr 2023
TL;DR: In 2019 and 2020, field research campaigns collected hourly atmospheric profiles via radiosonde surrounding the 2 July 2019 and 14 December 2020 total solar eclipses over South America from locations within the paths of eclipse totality as discussed by the authors .
Abstract: Abstract. Field research campaigns in 2019 and 2020 collected hourly atmospheric profiles via radiosonde surrounding the 2 July 2019 and 14 December 2020 total solar eclipses over South America from locations within the paths of eclipse totality. As part of these atmospheric data collection campaigns, the eclipse module of the Advanced Research Weather Research & Forecast (WRF-ARW) model was utilized to model meteorological conditions before, during, and after the eclipse events. The surface and upper air measurements collected through these campaigns have enabled further assessment and validation of the WRF-ARW eclipse module’s performance in simulating atmospheric responses to total solar eclipses. We provide here descriptions of both field campaigns and present results from comparisons of meteorological variables both at the surface and aloft using observational datasets obtained through the campaigns. The paper concludes by recommending further scientific analyses to be explored utilizing the unique datasets presented.
TL;DR: The total electron content (TEC) derived from ground-based BeiDou geostationary orbit (GEO) satellite receivers lying on both sides of the eclipse path is used to study the ionospheric variations in southern China, particularly targeting eclipse-induced gravity waves in the ionosphere during the annular solar eclipse on 21 June 2020 as discussed by the authors .
Abstract: The total electron content (TEC) derived from ground-based BeiDou geostationary orbit (GEO) satellite receivers lying on both sides of the eclipse path is used to study the ionospheric variations in southern China, particularly targeting eclipse-induced gravity waves in the ionosphere during the annular solar eclipse on 21 June 2020. Eclipse-induced gravity waves (GWs) signatures with periods of about 70 min, from wavelet analysis, were identified on both sides of TEC observations, which are most likely to be induced in the thermosphere. However, there were significant differences in the intensity of the gravity waves on both sides of the eclipse path, gravity waves are stronger on the northern side of the eclipse path than on the southern side. Moreover, a postponement of TEC depletion shows on the northern side of the eclipse path which is caused by the convergence effect of the wind field. And at the same obstruction rate, GWs possibly can slightly adjust the postponement of TEC depletion on a small scale.
08 Jun 2023
TL;DR: In this article , the authors investigated variations of ionospheric Total Electron Content (TEC) and Ionospheric Scintillation Index S4 during the annular solar eclipse that occurred on 21st June 2020 over selected sites.
Abstract: Abstract In this study, we utilized both ground‐based and space‐borne observations including total electron content (TEC) from GPS satellites. We investigate in detail variations of ionospheric Total Electron Content (TEC) and Ionospheric Scintillation Index S4 during the annular Solar eclipse that occurred on 21st June 2020 over selected sites. We choose six stations MTAL, KIT3, and MADK in Uzbekistan, and JFNG, LHAZ, and BJFS in China which are located close to the path of the Solar eclipse with obscuration $52\%$, $57\%$, $58\%$, and $92\%$, $94\%$ and $95\%$, respectively. The Ionospheric parameters as TEC and S4 index have been analyzed for continuous three days from 20th to 22nd June 2020. A significant amount of depletion in TEC of the order of 10-30 $\%$ has been observed concerning the solar eclipse day. The results of the performed analysis indicate that the TEC level and S4 scintillation index were decreased during the solar eclipse due to the contraction of ionizing radiation.
26 Jun 2023
TL;DR: In 2019 and 2020, field research campaigns collected hourly atmospheric profiles via radiosonde surrounding the 2 July 2019 and 14 December 2020 total solar eclipses over South America from locations within the paths of eclipse totality as discussed by the authors .
Abstract: Abstract. Field research campaigns in 2019 and 2020 collected hourly atmospheric profiles via radiosonde surrounding the 2 July 2019 and 14 December 2020 total solar eclipses over South America from locations within the paths of eclipse totality. As part of these atmospheric data collection campaigns, the eclipse module of the Advanced Research Weather Research & Forecast (WRF-ARW) model was utilized to model meteorological conditions before, during, and after the eclipse events. The surface and upper air measurements collected through these campaigns have enabled further assessment and validation of the WRF-ARW eclipse module’s performance in simulating atmospheric responses to total solar eclipses. We provide here descriptions of both field campaigns and present results from comparisons of meteorological variables both at the surface and aloft using observational datasets obtained through the campaigns. The paper concludes by recommending further scientific analyses to be explored utilizing the unique datasets presented.
TL;DR: In this paper , the authors present a survey of the state of the art in the field of data collection and analysis of data collected from the World Wide Web, including the following data sets:
Abstract: Аннотация. Солнечное затмение оказывает влияние на верхнюю атмосферу Земли. Преимуществом такого естественного воздействия является то, что время затмения можно рассчитать заранее и подготовиться к экспериментам. Динамические процессы во время каждого затмения зависят от гелиогеофизической обстановки. Радиоволны диапазона ОНЧ способны распространяться на тысячи километров в волноводе Земля – ионосфера. Расположение ОНЧ радиотрасс определяет пространство для мониторинга нижней ионосферы (как части верхней атмосферы). Исследовались вариации амплитуд ОНЧ радиосигналов, принимаемых в Якутске от передатчиков DHO (23,4 кГц, 53,08° N, 7,62° E) и JXN (16,4 кГц, 66,97° N, 13,87° E). Большая часть этих радиотрасс располагается на арктической территории Евразии. Зарегистрированные суточные вариации амплитуды ОНЧ сигналов DHO и JXN с 7 по 13 июня 2021 г. объясняются вариацией потока ионизирующего излучения солнца, интерференцией мод высших порядков при прохождении восходного и заходного терминаторов по участкам радиотрасс, а также режимом работы передатчиков. В период солнечного затмения 10 июня 2021 г. минимальное среднее значение отношения площадей открытой части диска Солнца к полной составило 0,532 (11:39:18 UTC) и 0,411 (11:33:00 UTC) вдоль радиотрасс DHO – Якутск и JXN – Якутск соответственно. Эффект затмения проявился в виде повышения амплитуды в максимуме на 1,62 дБ (11:39:18 UTC) и 1,4 дБ (11:26:42 UTC) для сигналов DHO и JXN соответственно. Малые затраты на изготовление ОНЧ приемников, возможность охвата больших территорий делают регистрацию ОНЧ сигналов удобным инструментом для зондирования нижней ионосферы над труднодоступными и малонаселенными территориями.
Abstract. A solar eclipse affects the Earth's upper atmosphere. The eclipse time can be calculated in advance, which allows us to prepare for experiments. Dynamic processes during each specific eclipse depend on the heliogeophysical environment. VLF radio waves can propagate thousands of kilometers in the Earth-ionosphere waveguide. The location of the VLF radio paths determines the space for monitoring the lower ionosphere (as a part of the upper atmosphere). We applied a method of studying the amplitude variation of VLF radio signals from DHO (23.4 kHz, 53.08° N, 7.62° E) and JXN (16.4 kHz, 66.97° N, 13.87° E) transmitters received in Yakutsk. The most part of these radio paths is located along the Arctic territory of Eurasia. The diurnal VLF amplitude variations of the DHO и JXN signals from June 7 to 13 are explained by the solar ionizing flux variation, the higher-order modes interference during the passage of the rising and setting terminators along the elements of the radio paths, and the transmitters operating mode. During the solar eclipse of June 10, 2021, the minimum average ratio value of the open part of the solar disk area to the full disk area was 0.532 (11:39:18 UTC) and 0.411 (11:33:00 UTC) along the DHO – Yakutsk and JXN – Yakutsk radio paths, respectively. The eclipse effect appeared as an amplitude increase at the maximum of 1.62 dB (11:39:18 UTC) and 1.4 dB (11:26:42 UTC) for the DHO and JXN signals, respectively. Furthermore, our data provide the low VLF receivers manufacturing costs and the ability to cover large areas make the VLF registration a convenient tool for sounding the lower ionosphere over the hard-to-reach and sparsely populated areas.
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TL;DR: Eclipse Chasers as discussed by the authors is a guide to past and future Australian total solar eclipses, exploring historical and cultural knowledge, as well as featuring five upcoming eclipses that will be visible in Australia.
Abstract: Witnessing a total solar eclipse is a wondrous and unforgettable event!
Eclipse Chasers is a guide to past and future Australian total solar eclipses, exploring historical and cultural knowledge, as well as featuring five upcoming eclipses that will be visible in Australia.
The science of eclipses is explained, as well as how to prepare for an eclipse and view it safely. For upcoming eclipses the best locations to view each one are revealed, alongside tips for taking photographs.
The book also reveals untold stories of how past Australian astronomers observed the total eclipses that have occurred since European settlement, and how these eclipses were celebrated in popular culture, poetry and art. It explores the great significance of solar eclipses for First Nations peoples, and their observations and cultural meanings.
Eclipse Chasers showcases the drama and beauty of total solar eclipses and is essential for anyone fascinated by these amazing events.
01 Jan 2023
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TL;DR: In 2019 and 2020, field research campaigns collected hourly atmospheric profiles via radiosonde surrounding the 2 July 2019 and 14 December 2020 total solar eclipses over South America from locations within the paths of eclipse totality as mentioned in this paper .
Abstract: Abstract. Field research campaigns in 2019 and 2020 collected hourly atmospheric profiles via radiosonde surrounding the 2 July 2019 and 14 December 2020 total solar eclipses over South America from locations within the paths of eclipse totality. As part of these atmospheric data collection campaigns, the eclipse module of the Advanced Research Weather Research & Forecast (WRF-ARW) model was utilized to model meteorological conditions before, during, and after the eclipse events. The surface and upper air measurements collected through these campaigns have enabled further assessment and validation of the WRF-ARW eclipse module’s performance in simulating atmospheric responses to total solar eclipses. We provide here descriptions of both field campaigns and present results from comparisons of meteorological variables both at the surface and aloft using observational datasets obtained through the campaigns. The paper concludes by recommending further scientific analyses to be explored utilizing the unique datasets presented.
TL;DR: In this article , the authors investigated the lower ionospheric response to the annular solar eclipse of December 26, 2019 (ASE19) by analyzing VLF phase modulation as observed from four different locations in India during the campaign organized by the Indian Centre for Space Physics (ICSP), Kolkata.