SOLAR ECLIPSE OBSERVATIONS OF THE IONOSPHERE

1948 ◽  
Vol 26a (3) ◽  
pp. 137-144 ◽  
Author(s):  
C. W. McLeish
Keyword(s):  
Solar Eclipse ◽  
Variable Coefficient ◽  
Negative Ion ◽  
Ion Density ◽  
Eclipse Observations ◽  
E Region ◽  
Made In

The results are presented of ionosphere measurements made in the region of totality during the eclipse of July 9, 1945. An analysis of the results shows effective recombination coefficients of 1.6 × 10−8 for E region, 1.4 × 10−8 for F1 region, and 1.0 × 10−9 for F2 region. Evidence of a variable coefficient for E region agrees with the suggestion of Massey and others of a high negative ion density at this level.

scholarly journals The ionospheric responses to the 11 August 1999 solar eclipse: observations and modeling

2008 ◽  
Vol 26 (1) ◽  
pp. 107-116 ◽  
Author(s):  
H. Le ◽  
L. Liu ◽  
X. Yue ◽  
W. Wan
Keyword(s):  
Theoretical Model ◽  
Solar Radiation ◽  
Solar Eclipse ◽  
Ionospheric Disturbance ◽  
Low Latitude ◽  
Ionospheric Response ◽  
Latitude Range ◽  
Eclipse Observations ◽  
E Region ◽  
Low Latitude Ionosphere

Abstract. A total eclipse occurred on 11 August 1999 with its path of totality passing over central Europe in the latitude range 40°–50° N. The ionospheric responses to this eclipse were measured by a wide ionosonde network. On the basis of the measurements of foE, foF1, and foF2 at sixteen ionosonde stations in Europe, we statistically analyze the variations of these parameters with a function of eclipse magnitude. To model the eclipse effects more accurately, a revised eclipse factor, FR, is constructed to describe the variations of solar radiation during the solar eclipse. Then we simulate the effect of this eclipse on the ionosphere with a mid- and low-latitude ionosphere theoretical model by using the revised eclipse factor during this eclipse. Simulations are highly consistent with the observations for the response in the E-region and F1-region. Both of them show that the maximum response of the mid-latitude ionosphere to the eclipse is found in the F1-region. Except the obvious ionospheric response at low altitudes below 500 km, calculations show that there is also a small response at high altitudes up to about 2000 km. In addition, calculations show that when the eclipse takes place in the Northern Hemisphere, a small ionospheric disturbance also appeared in the conjugate hemisphere.

Positive Corona and Atmospheric Negative Ion Density under Repetitive Impulse Conditions

1987 ◽  
Vol IA-23 (6) ◽  
pp. 990-994 ◽  
Author(s):  
Norman L. Allen ◽  
Gerard Berger ◽  
Derek Dring
Keyword(s):  
Negative Ion ◽  
Ion Density

Cavity ring-down spectroscopy to measure negative ion density in a helicon plasma source for fusion neutral beams

2018 ◽  
Vol 89 (10) ◽  
pp. 103504 ◽  
Author(s):  
R. Agnello ◽  
M. Barbisan ◽  
I. Furno ◽  
Ph. Guittienne ◽  
A. A. Howling ◽  
...  
Keyword(s):  
Plasma Source ◽  
Negative Ion ◽  
Cavity Ring Down Spectroscopy ◽  
Helicon Plasma ◽  
Ion Density ◽  
Neutral Beams ◽  
Cavity Ring Down

scholarly journals Effects of solar eclipse on the electrodynamical processes of the equatorial ionosphere: a case study during 11 August 1999 dusk time total solar eclipse over India

2002 ◽  
Vol 20 (12) ◽  
pp. 1977-1985 ◽  
Author(s):  
R. Sridharan ◽  
C. V. Devasia ◽  
N. Jyoti ◽  
Diwakar Tiwari ◽  
K. S. Viswanathan ◽  
...  
Keyword(s):  
Electric Fields ◽  
Solar Eclipse ◽  
Equatorial Ionosphere ◽  
Hf Radar ◽  
F Region ◽  
Large Enhancement ◽  
Temporal Structures ◽  
E Region ◽  
Field Lines ◽  
Electric Fields And Currents

Abstract. The effects on the electrodynamics of the equatorial E- and F-regions of the ionosphere, due to the occurrence of the solar eclipse during sunset hours on 11 August 1999, were investigated in a unique observational campaign involving ground based ionosondes, VHF and HF radars from the equatorial location of Trivandrum (8.5° N; 77° E; dip lat. 0.5° N), India. The study revealed the nature of changes brought about by the eclipse in the evening time E- and F-regions in terms of (i) the sudden intensification of a weak blanketing ES-layer and the associated large enhancement of the VHF backscattered returns, (ii) significant increase in h' F immediately following the eclipse and (iii) distinctly different spatial and temporal structures in the spread-F irregularity drift velocities as observed by the HF radar. The significantly large enhancement of the backscattered returns from the E-region coincident with the onset of the eclipse is attributed to the generation of steep electron density gradients associated with the blanketing ES , possibly triggered by the eclipse phenomena. The increase in F-region base height immediately after the eclipse is explained as due to the reduction in the conductivity of the conjugate E-region in the path of totality connected to the F-region over the equator along the magnetic field lines, and this, with the peculiar local and regional conditions, seems to have reduced the E-region loading of the F-region dynamo, resulting in a larger post sunset F-region height (h' F) rise. These aspects of E-and F-region behaviour on the eclipse day are discussed in relation to those observed on the control day.Key words. Ionosphere (electric fields and currents; equatorial ionosphere; ionospheric irregularities)

scholarly journals On the Coronal and Prominence Structures Observed at the Total Solar Eclipse of 11 July 1991

1994 ◽  
Vol 154 ◽  
pp. 205-210
Author(s):  
Y. Suematsu ◽  
H. Fukushima ◽  
Y. Nishino
Keyword(s):  
Solar Eclipse ◽  
Near Infrared ◽  
Thermal Structure ◽  
Wavelength Region ◽  
Total Solar Eclipse ◽  
Preliminary Results ◽  
Spectroscopic Observations ◽  
Physical Conditions ◽  
Made In

Coronal images were taken in the light of the He I 10830 Å line, the 10000 Å continuum, and the Fe XIV 5303 Å line, with the aim of studying the thermal structure of the corona. In addition, spectroscopic observations were made in the violet wavelength region (3760-4060 Å) and near-infrared (10745-10835 Å), to obtain details of physical conditions of the corona, especially of its cool part. The data obtained do not show any distinct cool structures other than ordinary prominences. Some preliminary results concerning the corona and prominence structures are given.

scholarly journals Effects of Negative Ion Density Control on Statistical Three Lags of Positive Impulse Corona in Dry Air

1999 ◽  
Vol 119 (4) ◽  
pp. 451-457 ◽  
Author(s):  
Jian-bo Yang ◽  
Hiroyasu Katase ◽  
Tatsuya Mori ◽  
Yasuji Izawa ◽  
Kiyoto Nishijima
Keyword(s):  
Negative Ion ◽  
Ion Density ◽  
Dry Air ◽  
Density Control

scholarly journals E-Region Field-Aligned Irregularities in the Middle of a Solar Eclipse Observed by a Bistatic Radar

2022 ◽  
Vol 14 (2) ◽  
pp. 392
Author(s):  
Lei Qiao ◽  
Gang Chen ◽  
Wanlin Gong ◽  
Xuesi Cai ◽  
Erxiao Liu ◽  
...  
Keyword(s):  
Solar Eclipse ◽  
Recovery Phase ◽  
Bistatic Radar ◽  
Doppler Shifts ◽  
Propagation Parameters ◽  
E Region ◽  
Gradient Drift ◽  
Drift Instability ◽  
Wave Induced ◽  
Field Aligned Irregularities

The Wuhan Ionospheric Oblique Backscatter Sounding System (WIOBSS) was applied as a bistatic radar to record the ionospheric E-region responses to a solar eclipse on 22 July 2009. The transmitter was located in Wuhan and the receiver was located in Huaian. The receiver observed anomalous echoes with larger Doppler shifts at the farther ranges compared with the echoes reflected by Es. According to the simulated ray propagation paths of the reflected and scattered waves, we considered that the anomalous echoes were scattered by E-region field-aligned irregularities (FAIs). The locations of the FAIs recorded by the WIOBSS were estimated with the International Geomagnetic Reference Field (IGRF) and the observed propagation parameters. These irregularities occurred at around the eclipse maximum and lasted for ~20–40 min. The steep plasma density gradient induced by the fast drop photo ionization under the lunar shadow was beneficial to the occurrence of gradient drift instability to generate the FAIs. They were different from the gravity wave-induced irregularities occurring in the recovery phase of the solar eclipse.

Experimental evidence for the role of ions in particle nucleation under atmospheric conditions

2006 ◽  
Vol 463 (2078) ◽  
pp. 385-396 ◽  
Author(s):  
Henrik Svensmark ◽  
Jens Olaf P Pedersen ◽  
Nigel D Marsh ◽  
Martin B Enghoff ◽  
Ulrik I Uggerhøj
Keyword(s):  
Sulphur Dioxide ◽  
Aerosol Particles ◽  
Experimental Studies ◽  
Negative Ion ◽  
Cloud Formation ◽  
Particle Nucleation ◽  
Atmospheric Conditions ◽  
Ion Density ◽  
Stable Clusters

Experimental studies of aerosol nucleation in air, containing trace amounts of ozone, sulphur dioxide and water vapour at concentrations relevant for the Earth's atmosphere, are reported. The production of new aerosol particles is found to be proportional to the negative ion density and yields nucleation rates of the order of 0.1–1 cm −3  s −1 . This suggests that the ions are active in generating an atmospheric reservoir of small thermodynamically stable clusters, which are important for nucleation processes in the atmosphere and ultimately for cloud formation.

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