Lower thermospheric composition changes derived from optical and radar data taken at Sondre Stromfjord during the Great Magnetic Storm of February 1986

1991 ◽  
Vol 96 (A4) ◽  
pp. 5757 ◽  
Author(s):  
J. H. Hecht ◽  
D. J. Strickland ◽  
A. B. Christensen ◽  
D. C. Kayser ◽  
R. L. Walterscheid
Keyword(s):  
Magnetic Storm ◽  
Radar Data ◽  
Composition Changes

Multi-Step Dst Development and Ring Current Composition Changes During the 4-6 Jun 1991 Magnetic Storm

2001 ◽  
Author(s):  
J. U. Kozyra ◽  
M. W. Liemohn ◽  
C. R. Clauer ◽  
J. Ridley ◽  
M. F. Thomsen
Keyword(s):  
Magnetic Storm ◽  
Ring Current ◽  
Composition Changes

scholarly journals Positive storm effects in the dayside polar ionospheric F-region observed by EISCAT and ESR during the magnetic storm of 15 May 1997

2002 ◽  
Vol 20 (9) ◽  
pp. 1377-1384 ◽  
Author(s):  
S. Y. Ma ◽  
H. T. Cai ◽  
H. X. Liu ◽  
K. Schlegel ◽  
G. Lu
Keyword(s):  
Electron Temperature ◽  
Magnetic Storm ◽  
Radar Data ◽  
Auroral Oval ◽  
Soft Particle ◽  
Plasma Convection ◽  
Particle Precipitation ◽  
Storm Effects ◽  
Cusp Region ◽  
F Region

Abstract. EISCAT/ESR radar data and in situ FAST and POLAR satellite observations are coordinately analyzed to investigate positive ionospheric storm effects in the dayside upper F-region in both the polar cap and the auroral oval during the magnetic storm of 15 May 1997. An ionization enhancement, lasting for about 2.5 h, appeared first over the EISCAT site around magnetic noon; about one hour later, a similar ionization enhancement was also seen over ESR. During the concerned time period ion energy spectra measured on board FAST show clearly continuous energy-latitude dispersion when the satellite passed by over the EISCAT latitude. This implies that EISCAT was located under the polar cusp region which was highly active, and expanded greatly equatorwards due to magnetopause reconnections during long-lasting southward IMF. Simultaneously, soft particles of the magnetosheath precipitated into the F-region ionosphere and caused the positive storm effects over EISCAT. The coincident increase in electron temperature at EISCAT gives additional evidence for soft particle precipitation. Consistently, POLAR UV images show strong dayside aurora extending to as low as 62° N magnetic latitude. The ionization enhancement over ESR, however, seems not to be caused by local particle precipitation, evidenced by a lack of enhanced electron temperature. The observed plasma convection velocity and data-fitted convection patterns by AMIE suggested that it is likely to be a polar patch originating from the cusp region and traveling to the ESR site.Key words. Ionosphere (auroral ionosphere; particle percipitation) Magnetospheric physics (storms and substorms)

scholarly journals MultistepDstdevelopment and ring current composition changes during the 4-6 June 1991 magnetic storm

2002 ◽  
Vol 107 (A8) ◽  
pp. SMP 33-1-SMP 33-22 ◽  
Author(s):  
J. U. Kozyra ◽  
M. W. Liemohn ◽  
C. R. Clauer ◽  
A. J. Ridley ◽  
M. F. Thomsen ◽  
...  
Keyword(s):  
Magnetic Storm ◽  
Ring Current ◽  
Composition Changes

Modelling of thermospheric composition changes caused by a severe magnetic storm

1985 ◽  
Vol 33 (11) ◽  
pp. 1283-1301 ◽  
Author(s):  
H. Rishbeth ◽  
R. Gordon ◽  
D. Rees ◽  
T.J. Fuller-Rowell
Keyword(s):  
Magnetic Storm ◽  
Composition Changes

Characteristics of a HSS-driven magnetic storm in the high-latitude ionosphere; A case study of 14th of March 2016 storm

2020 ◽  
Author(s):  
Nada Ellahouny ◽  
Anita Aikio ◽  
Marcus Pedersen ◽  
Heikki Vanhamäki ◽  
Ilkka Virtanen ◽  
...  
Keyword(s):  
Solar Wind ◽  
Magnetic Storm ◽  
High Speed ◽  
Radar Data ◽  
Geomagnetic Disturbances ◽  
Plasma Parameters ◽  
D Region ◽  
High Latitude Ionosphere ◽  
Eiscat Radar ◽  
Cosmic Noise

<p> Solar wind High-Speed Streams (HSSs) affect the auroral ionosphere in many ways, and several separate studies have been conducted of the different effects seen e.g. on aurora, geomagnetic disturbances, F-region behavior, and energetic particle precipitation. In this work, we study an HSS event in the solar cycle (24), which was associated with a co-rotating interaction region (CIR) that hit the Earth’s magnetopause at about 17:20 UT on 14 March 2016. The associated magnetic storm lasted for seven days, and the Dst index reached -56 nT. We use a very comprehensive set of measurements to study the whole period of this storm, following day by day for the magnetic indices and solar wind parameters and relating its consequences on ionospheric plasma parameters. We use EISCAT radar data from Tromsø and Svalbard stations to see the response in plasma parameters at different altitudes, riometer data for cosmic noise absorption, and IMAGE magnetometers to see the intensities of auroral electrojets. TomoScand ionospheric tomography provides us with electron densities over a wide region in Scandinavia and AMPERE data the global field-aligned currents. We identified 13 local substorms in the Scandinavian sector from the IL (IMAGE lower) index. Altogether, there were 11 global substorms, for which the AE index reaches 1000 nT. We discuss the development of currents, as well as E and D region precipitation during the course of this long-duration storm and compare local versus global behavior.</p>

Problems in Thin-Film X-ray Quantification

1990 ◽  
Vol 48 (2) ◽  
pp. 458-459
Author(s):  
J N Chapman ◽  
W A P Nicholson
Keyword(s):  
Thin Film ◽  
Specimen Thickness ◽  
X Rays ◽  
Characteristic Peak ◽  
Local Composition ◽  
X Ray ◽  
Measured Ratio ◽  
Path Lengths ◽  
Composition Changes

Energy dispersive x-ray microanalysis (EDX) is widely used for the quantitative determination of local composition in thin film specimens. Extraction of quantitative data is usually accomplished by relating the ratio of the number of atoms of two species A and B in the volume excited by the electron beam (nA/nB) to the corresponding ratio of detected characteristic photons (NA/NB) through the use of a k-factor. This leads to an expression of the form nA/nB = kAB NA/NB where kAB is a measure of the relative efficiency with which x-rays are generated and detected from the two species.Errors in thin film x-ray quantification can arise from uncertainties in both NA/NB and kAB. In addition to the inevitable statistical errors, particularly severe problems arise in accurately determining the former if (i) mass loss occurs during spectrum acquisition so that the composition changes as irradiation proceeds, (ii) the characteristic peak from one of the minority components of interest is overlapped by the much larger peak from a majority component, (iii) the measured ratio varies significantly with specimen thickness as a result of electron channeling, or (iv) varying absorption corrections are required due to photons generated at different points having to traverse different path lengths through specimens of irregular and unknown topography on their way to the detector.

Potentialities of the comparison of «Sich-1M» side looking radar data and foreign satellite information

2004 ◽  
Vol 10 (2-3) ◽  
pp. 93-100
Author(s):  
V.V. Malynovskyi ◽  
◽  
V.P. Zubko ◽  
V.V. Pustovoitenko ◽  
◽  
...  
Keyword(s):  
Radar Data ◽  
Satellite Information ◽  
Side Looking Radar

INTELLIGENT ANALYSIS OF RADAR DATA BASED ON FUZZY TRANSFORMS

2018 ◽  
Vol 77 (15) ◽  
pp. 1321-1329 ◽  
Author(s):  
S.V. Solonskaya ◽  
V. V. Zhirnov
Keyword(s):  
Radar Data ◽  
Intelligent Analysis
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