scholarly journals Observation of the prominence cavity region using slitless eclipse flash spectra and space borne EUV filtergrams

2013 ◽  
Vol 8 (S300) ◽  
pp. 151-154
Author(s):  
Cyrille Bazin ◽  
Serge Koutchmy ◽  
Philippe Lamy ◽  
Ehsan Tavabi
Keyword(s):  
Electron Density ◽  
Plasma Density ◽  
Solar Eclipse ◽  
Intensity Ratio ◽  
Radial Direction ◽  
Hydrostatic Equilibrium ◽  
Total Solar Eclipse ◽  
First Time ◽  
The Continuum

AbstractWe used total solar eclipse free of parasitic light for studying the prominence to corona interface, and the corresponding cavity in the context of the coronal physics. We analysed the visible continuum between the prominences to directly look at the electron density. We demonstrate some enhanced heating in the cavity region. Some similarities with the interface regions are shown: the photosphere to the chromosphere and the prominence to the corona interface. The optically thin neutral Helium at 4713 Å and the singly ionized Helium 4686 Å Paschen α lines are considered. We summed 80 slitless visible eclipse flash spectra that we compare with simultaneously obtained EUV SWAP/Proba2 174 Å images of ESA and AIA/SDO 171Å 193 Å 304 Å and 131 Å filtergrams. Intensity profiles in a radial direction are studied. We deduce the variation of the intensity ratio I(He I 4713) / I(He II 4686). Discussion: the temperature rises at the edge of the prominences. We evaluate for the first time with spectrophotometric accuracy the continuum modulations in prominence spectra. W-L intensity deficits are observed near the prominence boundaries in both eclipse spectra and in EUV images, confirming that the prominence -cavity regions correspond to a relative depression of plasma density of the surrounding corona. Conclusion: we demonstrate some enhanced heating occurring in these regions assuming hydrostatic equilibrium.

scholarly journals Mapping prominence plasma parameters from eclipse observations

2013 ◽  
Vol 8 (S300) ◽  
pp. 420-421
Author(s):  
Sonja Jejčič ◽  
Petr Heinzel ◽  
Maciej Zapiór ◽  
Miloslav Druckmüller ◽  
Stanislav Gunár ◽  
...  
Keyword(s):  
Visible Light ◽  
Electron Density ◽  
Solar Eclipse ◽  
Light Emission ◽  
Total Solar Eclipse ◽  
Quiescent Prominence ◽  
Plasma Parameters ◽  
Eclipse Observations ◽  
First Time ◽  
Visible Light Emission

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

scholarly journals Evidence of gravity waves into the atmosphere during the March 2006 total solar eclipse

2007 ◽  
Vol 7 (18) ◽  
pp. 4943-4951 ◽  
Author(s):  
C. S. Zerefos ◽  
E. Gerasopoulos ◽  
I. Tsagouri ◽  
B. E. Psiloglou ◽  
A. Belehaki ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Electron Density ◽  
Gravity Waves ◽  
Solar Eclipse ◽  
Stratospheric Ozone ◽  
Thermal Fluctuations ◽  
Ozone Layer ◽  
Total Solar Eclipse ◽  
Electron Content ◽  
Total Electron

Abstract. This study aims at providing experimental evidence, to support the hypothesis according to which the movement of the moon's shadow sweeping the ozone layer at supersonic speed, during a solar eclipse, creates gravity waves in the atmosphere. An experiment was conducted to study eclipse induced thermal fluctuations in the ozone layer (via measurements of total ozone column, ozone photolysis rates and UV irradiance), the ionosphere (Ionosonde Total Electron Content – ITEC, peak electron density height – hmF2), and the troposphere (temperature, relative humidity), before, during and after the total solar eclipse of 29 March 2006. We found the existence of eclipse induced dominant oscillations in the parameters related to the ozone layer and the ionosphere, with periods ranging between 30–40 min. Cross-spectrum analyses resulted to statistically significant square coherences between the observed oscillations, strengthening thermal stratospheric ozone forcing as the main mechanism for GWs. Additional support for a source below the ionosphere was provided by the amplitude of the oscillations in the ionospheric electron density, which increased upwards from 160 to 220 km height. Even though similar oscillations were shown in surface temperature and relative humidity data, no clear evidence for tropospheric influence could be derived from this study, due to the modest amplitude of these waves and the manifold rationale inside the boundary layer.

scholarly journals Evidence of gravity waves into the atmosphere during the March 2006 total solar eclipse

2007 ◽  
Vol 7 (3) ◽  
pp. 7603-7624 ◽  
Author(s):  
C. S. Zerefos ◽  
E. Gerasopoulos ◽  
I. Tsagouri ◽  
B. Psiloglou ◽  
A. Belehaki ◽  
...  
Keyword(s):  
Electron Density ◽  
Gravity Waves ◽  
Solar Eclipse ◽  
Ozone Layer ◽  
Total Solar Eclipse ◽  
Electron Content ◽  
Supersonic Speed ◽  
Ionospheric Electron Density ◽  
Total Electron ◽  
Phase Spectra

Abstract. This study aims at testing the hypothesis according to which the movement of the moon's shadow sweeping the ozone layer at supersonic speed during a solar eclipse creates gravity waves in the atmosphere. An experiment was conducted to study fluctuations of the ozone layer, the Ionosonde Total Electron Content (ITEC) and the peak electron density height (hmF2) in the ionosphere, as well as at a number of other parameters before, during and after the total solar eclipse. We found the existence of dominant oscillations with periods ranging between 30–40 min in most of the parameters. Cross-spectrum analyses between total ozone and various atmospheric parameters resulted to statistically significant square coherences between the observed oscillations, while the respective phase spectra show that the perturbation originates in the stratosphere and reaches the various layers at speeds around 20 km min−1. Additional evidence supporting these findings was provided by the amplitude of the oscillations in the ionospheric electron density, which increased upwards from 160 to 220 km height.

scholarly journals 850 μm Observations of the 11 July 1991 Total Solar Eclipse

1994 ◽  
Vol 154 ◽  
pp. 161-166
Author(s):  
M. W. Ewell ◽  
H. Zirin ◽  
J. B. Jensen ◽  
T. S. Bastian
Keyword(s):  
Electron Density ◽  
Solar Eclipse ◽  
Scale Height ◽  
Total Solar Eclipse ◽  
Single Electron ◽  
Density Scale

We present observations of the 11 July 1991 total solar eclipse made from the Caltech Submillimeter Observatory. The 850 μm limb is extended 3380±140 km above the visible limb, and there is a 10% brightening at the extreme limb. The measured limb height agrees with previous work at shorter and longer wavelengths. The run of limb heights with wavelength is well fit by a single electron density scale height. We argue that there is no need to invoke spicule geometry to explain the observations.

scholarly journals New deep coronal spectra from the 2017 total solar eclipse

2019 ◽  
Vol 632 ◽  
pp. A86 ◽  
Author(s):  
S. Koutchmy ◽  
F. Baudin ◽  
Sh. Abdi ◽  
L. Golub ◽  
F. Sèvre
Keyword(s):  
Solar Wind ◽  
Solar Eclipse ◽  
Coronal Holes ◽  
Solar Limb ◽  
Total Solar Eclipse ◽  
Emission Lines ◽  
High Spectral Resolution ◽  
Doppler Shifts ◽  
Dust Component ◽  
The Continuum

Context. The origin of the high temperature of the solar corona, in both the inner bright parts and the more outer parts showing flows toward the solar wind, is not understood well yet. 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). Aims. 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 velocities, Doppler shifts, and abundances to constrain the proposed heating mechanisms and understand the origin of flows that lead to solar wind. Methods. We describe a slit spectroscopic experiment of high spectral resolution to provide an analysis of the most typical parts of the quasi-minimum type corona observed during the total solar eclipse of Aug. 21, 2017 from Idaho, USA. Streamers, active region enhancements, and polar coronal holes (CHs) are measured well using deep spectra. Results. Sixty spectra are obtained during the totality with a long slit, covering ±3 solar radii in the range of 510 nm to 590 nm. The K+F continuum corona is exposed well up to two solar radii. The F-corona can be measured even at the solar limb. New weak emission lines were discovered or confirmed. The rarely observed Ar X line is detected almost everywhere; the Fe XIV and Ni XIII lines are clearly detected everywhere. For the first time hot lines are also measured inside the CH regions. The radial variations of the non-thermal turbulent velocities of the lines do not show a great departure from the average values. No significantly large Doppler shifts are seen anywhere in the inner or the middle corona. The wings of the Fe XIV line show some non-Gaussianity. Conclusions. Deep slit coronal spectra offered an opportunity for diagnosing several aspects of coronal physics during a well observed total eclipse without extended investments. The analysis of the ionic emission line profiles offers several powerful diagnostics of the coronal dynamics; the precise measurement of the F-continuum component provides insight into the ubiquitous dust corona at the solar limb.

scholarly journals Attenuation of global ultraviolet and visible irradiance over Greece during the total solar eclipse of 29 March 2006

2007 ◽  
Vol 7 (23) ◽  
pp. 5959-5969 ◽  
Author(s):  
A. Kazantzidis ◽  
A. F. Bais ◽  
C. Emde ◽  
S. Kazadzis ◽  
C. S. Zerefos
Keyword(s):  
Solar Eclipse ◽  
Total Solar Eclipse ◽  
Model Calculations ◽  
Visible Part ◽  
Comparison Results ◽  
Close Proximity ◽  
Limb Darkening ◽  
First Time ◽  
D Model ◽  
Greek Island

Abstract. The variability of ultraviolet and photosynthetically active radiation (PAR) during the total solar eclipse of 29 March 2006 was examined in this study. The measurements from NILU-UV multichannel radiometers at 7 stations of the Greek UV Network were used, where the maximum eclipse percentage ranged from 73.1% to 94.8%. In addition, an extra instrument was established at a remote Greek island, Kastelorizo, which was within the Moon's umbral shadow. The reduction of irradiance at 305 and 312 nm relative to non-eclipse conditions at all sites was almost 1.5 times more than the corresponding decrease in the UVA and visible part of the spectrum and reached 98% for eclipse percentage equal to 94%. The availability of several instruments in close proximity to the path of the umbral shadow provided a challenging test for the models. The measured changes in UV and visible irradiance were compared with 1-D model calculations accounting for the limb darkening effect. The agreement between measurements and modeled values at all sites is within 3% for eclipse percentages of less than 30% and becomes worse as the eclipse progresses. The 1-D model reproduced the spectral effect of the eclipse in UVA and PAR wavelength regions within 3% for eclipse percentages up to 50%, but only the half of the observed change was captured as the eclipse progressed. At three sites, where the eclipse maximum was more than 94%, the measured irradiance at 305 nm for eclipse percentages of more than 85% decreased with slower rates than for longer wavelengths. As a result, the total ozone values, derived from the 305/320 nm ratios, apparently decreased significantly for high eclipse percentages. The effect is similar at all three sites, but the interpretation of this observation remains a challenge. Comparison results with 3-D model calculations shortly before, during and shortly after totality were performed for the first time and revealed an agreement with measurements within 20% in the UV-A region. However, the modeled estimates of irradiance at 312 nm are three times lower than measured values.

scholarly journals Surface Radiation during the Total Solar Eclipse over Ny-Ålesund, Svalbard, on 20 March 2015

2016 ◽  
Author(s):  
M. Maturilli ◽  
C. Ritter
Keyword(s):  
Solar Eclipse ◽  
Meteorological Data ◽  
High Arctic ◽  
Total Solar Eclipse ◽  
Surface Radiation ◽  
Test Case ◽  
Data Set ◽  
Radiation Data ◽  
Exchange Processes ◽  
First Time

Abstract. On 20 March 2015, a total solar eclipse occurred over Ny-Ålesund (78.9° N, 11.9° E), Svalbard, in the high Arctic. It has been the first time that the surface radiation components during the totality of a solar eclipse have been measured by a Baseline Surface Radiation Network (BSRN) station. With the Ny-Ålesund long term radiation data set as background (available at http://dx.doi.org/10.1594/PANGAEA.150000), we here present the peculiarities of the radiation components and basic meteorology observed during the eclipse event. The supplementary data set contains the basic BSRN radiation and surface meteorological data in 1-minute resolution for March 2015, and is available at http://dx.doi.org/10.1594/PANGAEA.854326. The eclipse radiation data will be a useful auxiliary data set for further studies on micro-meteorological surface-atmosphere exchange processes in the Svalbard environment, and may serve as a test case for radiative transfer studies.

Wave Steepening in Ionospheric Total Electron Density due to the 21 August 2017 Total Solar Eclipse

2021 ◽  
Vol 126 (3) ◽  
Author(s):  
Yang‐Yi Sun ◽  
Mitchell M. Shen ◽  
Yu‐Lin Tsai ◽  
Chi‐Yen Lin ◽  
Min‐Yang Chou ◽  
...  
Keyword(s):  
Electron Density ◽  
Solar Eclipse ◽  
Total Solar Eclipse ◽  
Total Electron Density ◽  
Total Electron
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