Detection of polarization neutral points in observations of the combined corona and sky during the 21 August 2017 total solar eclipse
Frans Snik, Steven P. Bos, Stefanie A. Brackenhoff, David S. Doelman, Emiel H. Por, Felix Bettonvil, Michiel Rodenhuis, Dmitry Vorobiev, Laura M. Eshelman, Joseph A. Shaw
备注：
Part of the Applied Optics special feature issue on Light and Color in Nature
发表信息：
Applied Optics Vol. 59, Issue 21, pp. F71-F77 (2020)
We report the results of polarimetric observations of the total solar eclipse of 21 August 2017 from Rexburg, Idaho (USA). We use three synchronized DSLR cameras with polarization filters oriented at 0°, 60°, and 120° to provide high-dynamic-range RGB polarization images of the corona and surrounding sky. We measure tangential coronal polarization and vertical sky polarization, both as expected. These observations provide detailed detections of polarization neutral points above and below the eclipsed Sun where the coronal polarization is canceled by the sky polarization. We name these special polarization neutral points after Minnaert and Van de Hulst.
During the outburst of V713 Cephei in August 2009 the times of 8 eclipses were measured and these, together with 5 eclipse timings obtained during quiescence in August 2007, provide an improved orbital period of 0.085418432(4)d. No superhumps were observed in the light curve indicating this was a normal UG-type dwarf nova outburst. We found the eclipse depth decreased linearly with rising system excitation level, falling from ~3 magnitudes in quiescence to ~2 magnitudes during outburst. The depth and totality of eclipses in quiescence suggests a high orbital inclination. We saw no variation in…
Coronal jets, which extend from the solar surface to beyond 2 $R_\odot$, were observed in the polar coronal hole regions during the total solar eclipse on 2017 August 21. In a time-series of white-light images of the corona spanning 70 minutes taken with our multi-site observations of this eclipse, six jets were found as narrow structures upwardly ejected with the apparent speed of about 450 km s$^{-1}$ in polar plumes. On the other hand, extreme-ultraviolet (EUV) images taken with the Atmospheric Image Assembly of the Solar Dynamics Observatory show that all of the eclipse jets were preceded …
In order to study the solar corona during eclipses, a new telescope was constructed. Three coronal images were obtained simultaneously from one objective of the telescope as the coronal radiation passed through three polarisers (whose transmission directions were turned through 0^{\circ}, 60^{\circ}, and 120^{\circ} to the chosen direction); one image without polariser was also obtained. The telescope was used to observe the solar corona during the eclipse of 1 August 2008. We obtained distributions of the polarisation brightness, K-corona brightness, degree of the K-corona polarisation and to…
During the total solar eclipse at Akademgorodok, Siberia, Russia, in 1 August 2008, we imaged the flash spectrum with a slitless spectrograph. We have spectroscopically determined the duration of totality, the epoch of the 2nd and 3rd contacts and the duration of the flash spectrum (63 s during ingress and 48 s during egress). Here we compare the 2008 flash spectra with those that we similarly obtained from the total solar eclipse of 29 March 2006, at Kastellorizo, Greece. Any changes of the intensity of the corona emission lines, in particularly those of [Fe X] and [Fe XIV], could give us val…
On August 21, 2017, the Airborne Infrared Spectrometer (AIR-Spec) observed the total solar eclipse at an altitude of 14 km from aboard the NSF/NCAR Gulfstream V research aircraft. The instrument successfully observed the five coronal emission lines that it was designed to measure: Si X 1.431 $μ$m, S XI 1.921 $μ$m, Fe IX 2.853 $μ$m, Mg VIII 3.028 $μ$m, and Si IX 3.935 $μ$m. Characterizing these magnetically sensitive emission lines is an important first step in designing future instruments to monitor the coronal magnetic field, which drives space weather events as well as coronal heating, struc…
On 21 August 2017 a total solar eclipse swept across the contiguous United States providing excellent opportunities for diagnostics of the Sun's corona. The Sun's coronal structure is notoriously difficult to observe except during solar eclipses; thus theoretical models must be relied upon for inferring the underlying magnetic structure of the Sun's outer atmosphere. These models are necessary for understanding the role of magnetic fields in the heating of the corona to a million degrees and generation of severe space weather. Here we present a methodology for predicting the structure of the c…
The coronal magnetic field, despite its overwhelming importance to the physics and dynamics of the corona, has only rarely been measured. Here, the electron density maps derived from images acquired during the total solar eclipse of August 21st, 2017 are employed to demonstrate a new technique to measure the 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 reconstructio…
We have studied the corona as seen at the eclipses of 1878, 1900, 1901 and others. These eclipses occurred during extended sunspot minimum conditions. We compare these data with those of the recent solar minimum corona, using data from the eclipses of July 22 2009 and August 1 2008. An attempt to characterize the global solar magnetic fields is made. We speculate on the origin of the non-dipolar structure seen in the 2008 and 2009 eclipse images.
We present the first remote sensing observations of the impact from a Coronal Mass Ejection (CME) on the thermodynamic properties of the solar corona between 1 and 3 Rs. Measurements of the Fe XI (789.2 nm) and Fe XIV (530.3 nm) emission were acquired with identical narrow-bandpass imagers at three observing sites during the 2017 August 21 Total Solar Eclipse. Additional continuum imagers were used to observe K+F corona scattering, which is critical for the diagnostics presented here. The total distance between sites along the path of totality was 1400 km, corresponding to a difference of 28 m…
The total solar eclipse of August 21st, 2017 was observed with a Digital Single Lens Reflex (DSLR) camera equipped with a linear polarizing filter. A method was developed to combine images acquired with 15 different exposure times (from 1/4000 sec to 4 sec), identifying in each pixel the best interval of detector linearity. The resulting mosaic image of the solar corona extends up to more than 5 solar radii, with a projected pixel size by 3.7 arcsec/pixel, and an effective image resolution by 10.2 arcsecs, as determined with visible $α-$Leo and $ν-$Leo stars. Image analysis shows that in the i…
Total solar eclipse (TSE) coronal large and small scale events were reported in the historical literature but a definite synoptic coverage was missing for studying a relationship with the more general magnetic context of the solar-disk. We here analyze temporal changes in the solar corona before, during, and after the total solar eclipse on 21 August 2017 from a set of ground-based and of space-borne observations. High-quality ground-based white-light (W-L) observations and a deep image processing allow us to reveal these changes for the first time with a fraction of a one-minute time resoluti…
We report observations of the total solar eclipse of 14 December 2020, during which a coronal mass ejection can be see n propagating. A comprehensive set of photographs covering a high dynamic range of exposure allow to characterize its dimensions. The displacement of the front can be seen occurring during the few minutes of totality.
We carried out polarimetric observations of the white-light corona during the total solar eclipses that occurred on 2017 August 21 and 2019 July 2, and successfully obtained data at two different sites for both eclipses. After eliminating the sky background, we derived the brightness, polarization brightness, and degree of the polarization of the K+F corona from just above the limb to approximately 4 $R_\odot$. Furthermore, we isolated the K- and F-corona with plausible degree of polarization of the K-corona. The field of view covering up to approximately 4 $R_\odot$ enabled us to compare the …
We report on a search for short-period intensity variations in the green-line FeXIV 530.3 nm emission from the solar corona during the 21 August 2017 total eclipse viewed from Idaho in the United States. Our experiment was performed with a much more sensitive detection system, and with better spatial resolution, than on previous occasions (1999 and 2001 eclipses), allowing fine details of quiet coronal loops and an active-region loop system to be seen. A guided 200-mm-aperture Schmidt-Cassegrain telescope was used with a state-of-the-art CCD camera having 16-bit intensity discrimination and a …
We discuss results stemming from observations of the white-light and [Fe XIV] emission corona during the total eclipse of the Sun of 2008 August 1, in Mongolia (Altaj region) and in Russia (Akademgorodok, Novosibirsk, Siberia). Corresponding to the current extreme solar minimum, the white-light corona, visible up to 20 solar radii, was of a transient type with well-pronounced helmet streamers situated above a chain of prominences at position angles 48, 130, 241 and 322 degrees. A variety of coronal holes, filled with a number of thin polar plumes, were seen around the poles. Furthering an orig…
We carried out white-light observations of the total solar eclipse on 13 November 2012 at two sites, where the totality occurred 35 minutes apart. We caught an ongoing coronal mass ejection (CME) and a pre-CME loop structure just before the eruption in the height range between 1-2 R_sun. The source region of CMEs was revealed to be in this height range, where the material and the magnetic field of CMEs were located before the eruption. This height range includes the gap between the extreme ultraviolet observations of the low corona and the spaceborne white-light observations of the high corona…
Visible coronal structure, in particular the spatial evolution of coronal streamers, provides indirect information about solar magnetic activity and the underlying solar dynamo. Their apparent absence of structure observed during the total eclipses of throughout the Maunder Minimum has been interpreted as evidence of a significant change in the solar magnetic field from that during modern cycles. Eclipse observations available from the more recent Dalton Minimum may be able to provide further information, sunspot activity being between the levels seen during recent cycles and in the Maunder Mi…
Ludendorff coronal flattening index of the Total Solar Eclipse (TSE) on March 9, 2016, was calculated at various distances in solar radius. As a result, we obtained the coronal flattening index $\left(ε=a+b\right)$ at a distance of 2 solar radii is 0.16. The $24^{th}$ solar cycle phase based on the 2016 TSE event obtained -0.64 which showed the corona is pre-minimum type. Resulted coronal flattening index value gives a predicted maximum amplitude of the monthly sunspot number ($W_{max}$) for the $25^{th}$ solar cycle to be $70\pm65$. Therefore, the solar activity for $25^{th}$ solar cycle pred…
We present an investigation of a coronal cavity observed above the western limb in the coronal red line Fe X 6374 Å using a telescope of Peking University and in the green line Fe XIV 5303 Å using a telescope of Yunnan Observatories, Chinese Academy of Sciences during the total solar eclipse on 2017 August 21. A series of magnetic field models are constructed based on the magnetograms taken by the Helioseismic and Magnetic Imager onboard the Solar Dynamics Observatory (SDO) one week before the eclipse. The model field lines are then compared with coronal structures seen in images taken by the …
Total solar eclipses (TSEs) provide a unique opportunity to quantify the properties of the K-corona (electrons), F-corona (dust) and E-corona (ions) continuously from the solar surface out to a few solar radii. We apply a novel inversion method to separate emission from the K- and F-corona continua using unpolarized total brightness (tB) observations from five 0.5 nm bandpasses acquired during the 2019 July 2 TSE between 529.5 nm and 788.4 nm. The wavelength dependence relative to the photosphere (i.e., color) of the F-corona itself is used to infer the tB of the K- and F-corona for each line-…
Measuring the global magnetic field of the solar corona remains exceptionally challenging. The fine-scale density structures observed in white light images taken during Total Solar Eclipses (TSEs) are currently the best proxy for inferring the magnetic field direction in the corona from the solar limb out to several solar radii (Rs). We present, for the first time, the topology of the coronal magnetic field continuously between 1 and 6 Rs, as quantitatively inferred with the Rolling Hough Transform (RHT) for 14 unique eclipse coronae that span almost two complete solar cycles. We find that the…
The flash spectrum of the solar chromosphere and corona was measured with a slitless spectrograph before, after, and during the totality of the solar eclipse, of 11 July 2010, at Easter Island, Chile. This eclipse took place at the beginning of the Solar Cycle 24, after an extended minimum of solar activity. The spectra taken during the eclipse show a different intensity ratio of the red and green coronal lines compared with those taken during the total solar eclipse of 1 August 2008, which took place towards the end of the Solar Cycle 23. The characteristic coronal forbidden emission line of …
Coronal dimming of extreme ultraviolet (EUV) emission has the potential to be a useful forecaster of coronal mass ejections (CMEs). As emitting material leaves the corona, a temporary void is left behind which can be observed in spectral images and irradiance measurements. The velocity and mass of the CMEs should impact the character of those observations. However, other physical processes can confuse the observations. We describe these processes and the expected observational signature, with special emphasis placed on the differences. We then apply this understanding to a coronal dimming even…
Coronal density, temperature and heat flux distributions for the equatorial and polar corona have been deduced by Lemaire [2012] from Saito's model of averaged coronal white light (WL) brightness and polarization observations. They are compared with those determined from a kinetic collisionless/exospheric model of the solar corona. This comparison indicates rather similar distributions at large radial distances (> 7 Rs) in the collisionless region. However, rather important differences are found close to the Sun in the acceleration region of the solar wind. The exospheric heat flux is directed…
On 2019 July 2 a total solar eclipse -- visible across some parts of the Southern Pacific Ocean, Chile and Argentina -- will enable observations of the Sun's large-scale coronal structure. The structure of the Sun's corona and their emission characteristics are determined by underlying magnetic fields which also govern coronal heating and solar eruptive events. However, coronal magnetic field measurements remain an outstanding challenge. Computational models of coronal magnetic fields serve an important purpose in this context. Earlier work has demonstrated that the large-scale coronal field i…
This white paper is a call for a concerted effort to support total solar eclipse observations over the next decade, in particular for the 21 August 2017 eclipse which will traverse the US continent. With the recent advances in image processing techniques and detector technology, the time is ripe to capitalize on the unique diagnostic tools available in the visible and near infrared wavelength range to explore the physics of the corona. The advantage of coronal emission lines in this wavelength range, over their extreme ultraviolet counterparts, is (1) the significant radiative component in the…
Analysis of the solar coronal green line profiles reveals information regarding the physical conditions of the solar corona like temperature, density, Doppler velocity, non-thermal velocity etc. It provides insights to the unresolved problems like the coronal heating and the acceleration of the solar winds. Recent studies have reported excess blueshifts in the coronal line profiles and are interpreted as due to nanoflare heating, type II spicules and nascent solar wind flow. We have analyzed a time series of Fabry-Perot interferograms of the solar corona obtained during the total solar eclipse…
We present some new accurate CCD photometry analysis of the white light solar corona at the time of the last 20 March 2015 total eclipse (airborne observations on a Falcon 7X and at ground-based Svalbard). We measured coronal brightness profiles taken along radial directions from 1.001 to 3 solar radii in the northern, southern and equatorial regions, after removing the F corona and the sky background. These studies allow to evaluate the density gradients, structures and temperature heterogeneity, by considering the Thomson scattering in white light of the K corona and also emissions of the EU…
The state of the space environment plays a significant role for forecasting of geomagnetic storms produced by disturbances of the solar wind (SW). Coronal mass ejections (CMEs) passing through the heliosphere often have a prolonged (up to several days) trail with declining speed, which affects propagation of the subsequent SW streams. We studied the CME and the post-eruption plasma flows behind the CME rear in the event on 2010 August 18 observed in quadrature by several space-based instruments. Observations of the eruption in the corona with EUV telescopes and coronagraphs revealed several di…
Continuing our series of observations of the motion and dynamics of the solar corona over the solar-activity cycle, we observed the corona from sites in Queensland, Australia, during the 13 (UT)/14 (local time) November 2012 total solar eclipse. The corona took the low-ellipticity shape typical of solar maximum (flattening index ε = 0.01), showing a change from the composite coronal images that we had observed and analyzed in this journal and elsewhere for the 2006, 2008, 2009, and 2010 eclipses. After crossing the northeast Australian coast, the rest of the path of totality was over the ocean…
Large-scale Morphology of the Optical F-corona from a Total Solar Eclipse Observation During the Artemis II Lunar Flyby
Tokyo City University（东京都市大学）；Tohoku University（东北大学）；National Astronomical Observatory of Japan（日本国立天文台）；Ishigakijima Astronomical Observatory（石垣岛天文台）
Total eclipses permit a deep analysis of both the inner and the outer parts of the corona using the continuum White-Light (W-L) radiations from electrons (K-corona), the superposed spectrum of forbidden emission lines from ions (E-corona) and the dust component with F-lines (F-corona). By sufficiently dispersing the W-L spectrum, the Fraunhofer (F) spectrum of the dust component of the corona appears and the continuum Thomson radiation can be evaluated. The superposed emission lines of ions with different degrees of ionization are studied to allow the measurement of temperatures, non-thermal v…
Extensive X-ray and extreme ultraviolet (EUV) photometric observations of the eclipsing RS CVn system AR Lac were obtained over the years 1997 to 2013 with the Chandra X-ray Observatory Extreme Ultraviolet Explorer. During primary eclipse, HRC count rates decrease by ~40%. A similar minimum is seen during one primary eclipse observed by EUVE but not in others owing to intrinsic source variability. Little evidence for secondary eclipses is present in either the X-ray or EUV data, reminiscent of earlier X-ray and EUV observations. Primary eclipses allow us to estimate the extent of a spherically…
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 demonstrat…
We present a numerical investigation of the coronal evolution of a coronal mass ejection (CME) on 2005 August 22 using a 3-D thermodynamics magnetohydrodynamic model, the SWMF. The source region of the eruption was anemone active region (AR) 10798, which emerged inside a coronal hole. We validate our modeled corona by producing synthetic extreme ultraviolet (EUV) images, which we compare to EIT images. We initiate the CME with an out-of-equilibrium flux rope with an orientation and chirality chosen in agreement with observations of a H-alpha filament. During the eruption, one footpoint of the …
Total solar eclipses (TSEs) continue to provide an invaluable platform for exploring the magnetic topology of the solar corona and for studying dynamic events such as Coronal Mass Ejections (CMEs) -- with a higher spatial resolution over a larger spatially continuous extent than is possible to achieve with any other method at present. In this Letter, we present observations of the full extent of a `double-bubble' CME structure from the solar surface out to over 5 solar radii, as captured during the 2020 December 14 TSE. Its evolution through the corona was recorded from two observing sites sep…
The inner regions of the solar corona from 1-2.5 Rsun are poorly sampled both from the ground and space telescopes. A solar eclipse reduces the sky scattered background intensity by a factor of about 10,000 and opens a window to view this region directly. The goal of the Citizen {\it Continental-America Telescopic Eclipse} (CATE) Experiment is to take a 90-minute time sequence of calibrated white light images of this coronal region using 60 identical telescopes spread from Oregon to South Carolina during the 21 August 2017 total solar eclipse. Observations that can address questions of coronal…
The Airborne Infrared Spectrometer (AIR-Spec) offers an unprecedented opportunity to explore the Near Infra-Red (NIR) wavelength range. It has been flown at two total solar eclipses, in 2017 and 2019. The wavelength range of the much improved instrument on the second flight (July 2, 2019) was shifted to cover two density sensitive lines from S XI. In this paper we study detailed diagnostics for temperature, electron density and elemental abundances by comparing results from AIR-Spec slit positions above the east and the west limb with those from Hinode/EIS, the PolarCam detector and SDO/AIA. W…
We present coordinated coronal observations of the August 21, 2017 total solar eclipse with the Airborne Infrared Spectrometer (AIR-Spec) and the Extreme-ultraviolet Imaging Spectrometer (EIS). These instruments provide an unprecedented view of the solar corona in two disparate wavelength regimes, the near to mid infrared (IR) and the extreme ultraviolet (EUV), opening new pathways for characterizing the complex coronal plasma environment. During totality, AIR-Spec sampled coronal IR spectra near the equatorial west limb, detecting strong sources of Mg VIII, S XI, Si IX, and Si X in two passba…
We present the spatially resolved absolute brightness of the Fe X, Fe XI and Fe XIV visible coronal emission lines from 1.08 to 3.4 $R_\odot$, observed during the 2019 July 2 total solar eclipse (TSE). The morphology of the corona was typical of solar minimum, with a dipole field dominance showcased by large polar coronal holes and a broad equatorial streamer belt. The Fe XI line is found to be the brightest, followed by Fe X and Fe XIV (in disk $B_\odot$ units). All lines had brightness variations between streamers and coronal holes, where Fe XIV exhibited the largest variation. However, Fe X…
The Airborne Infrared Spectrometer (AIR-Spec) was commissioned during the 2017 total solar eclipse, when it observed five infrared coronal emission lines from a Gulfstream V (GV) research jet owned by the National Science Foundation (NSF) and operated by the National Center for Atmospheric Research (NCAR). The second AIR-Spec research flight took place during the July 2, 2019 total solar eclipse across the South Pacific. The 2019 eclipse flight resulted in seven minutes of observations, during which the instrument measured all four of its target emission lines: S XI 1.393 $μ$m, Si X 1.431 $μ$m…
Some 8000 images obtained with the SECIS fast-frame CCD camera instrument located at Lusaka, Zambia, during the total eclipse of 21 June 2001 have been analyzed to search for short-period oscillations in intensity that could be a signature of solar coronal heating mechanisms by MHD wave dissipation. Images were taken in white- light and Fe XIV green-line (5303 A) channels over 205 seconds (frame rate 39 s-1), approximately the length of eclipse totality at this location, with a pixel size of four arcseconds square. The data are of considerably better quality than were obtained during the 11 Au…
Using a potential field source surface (PFSS) model, we recently analyzed the global topology of the background coronal magnetic field for a sequence of coronal mass ejections (CMEs) that occurred on 2010 August 1-2. Here we repeat this analysis for the background field reproduced by a magnetohydrodynamic (MHD) model that incorporates plasma thermodynamics. As for the PFSS model, we find that all three CME source regions contain a coronal hole that is separated from neighboring coronal holes by topologically very similar pseudo-streamer structures. However, the two models yield very different …
Korea Astronomy and Space Science Institute (KASI) has been developing a next-generation coronagraph (NGC) in cooperation with NASA to measure the coronal electron density, temperature, and speed simultaneously using four different filters around 400 nm. KASI organized an expedition team to demonstrate the coronagraph measurement scheme and the instrumental technology through the 2017 total solar eclipse (TSE) across the USA. The observation site was in Jackson Hole, Wyoming, USA. We built an eclipse observation system, so-called Diagnostic Coronal Experiment (DICE), which is composed of two i…
Spectroscopic Observations of the Solar Corona during the 2017 August 21 Total Solar Eclipse: Comparison of Spectral Line Widths and Doppler Shifts Between Open and Closed Magnetic Structures
This Letter capitalizes on a unique set of total solar eclipse observations, acquired between 2006 and 2020, in white light, Fe XI 789.2 nm ($\rm T_{fexi}$ = $1.2 \pm 0.1$ MK) and Fe XIV 530.3 nm ($\rm T_{fexiv}$ = $ 1.8 \pm 0.1$ MK) emission, complemented by in situ Fe charge state and proton speed measurements from ACE/SWEPAM-SWICS, to identify the source regions of different solar wind streams. The eclipse observations reveal the ubiquity of open structures, invariably associated with Fe XI emission from $\rm Fe^{10+}$, hence a constant electron temperature, $\rm T_{c}$ = $\rm T_{fexi}$, in…
Eclipses are very favourable for the photosphere- chromosphere and corona interface observation as the occultation takes place in space, free of parasitic light coming from the occulting disk (the Moon). Independently, EUV filtergrams of the limb region obtained in space were analyzed using one dimensional hydrostatic VAL models but this method ignores the ubiquitous magnetic field emergence phenomenon associated with the chromospheric network. A jump of temperature from 0.01 to 1 MK is observed near the 2 Mm heights and higher, further producing a permanent solar wind flow. The heating proces…
Seven different models are applied to the same problem of simulating the Sun's coronal magnetic field during the solar eclipse on 2015 March 20. All of the models are non-potential, allowing for free magnetic energy, but the associated electric currents are developed in significantly different ways. This is not a direct comparison of the coronal modelling techniques, in that the different models also use different photospheric boundary conditions, reflecting the range of approaches currently used in the community. Despite the significant differences, the results show broad agreement in the ove…
The solar corona is a highly-structured plasma which can reach temperatures of more than ~2 MK. At low frequencies (decimetric and metric wavelengths), scattering and refraction of electromagnetic waves are thought to considerably increase the imaged radio source sizes (up to a few arcminutes). However, exactly how source size relates to scattering due to turbulence is still subject to investigation. The theoretical predictions relating source broadening to propagation effects have not been fully confirmed by observations due to the rarity of high spatial resolution observations of the solar c…
We study the interaction of two successive coronal mass ejections (CMEs) during the 2010 August 1 events using STEREO/SECCHI COR and HI data. We obtain the direction of motion for both CMEs by applying several independent reconstruction methods and find that the CMEs head in similar directions. This provides evidence that a full interaction takes place between the two CMEs that can be observed in the HI1 field-of-view. The full de-projected kinematics of the faster CME from Sun to Earth is derived by combining remote observations with in situ measurements of the CME at 1 AU. The speed profile …
