In Situ Observation Of Electrostatic Waves Associated With Ionospheric Plasma Irregularities

To study and characterise the ionospheric plasma irregularities at all latitudes, one can employ in-situ measurements by satellites in polar orbits, such as the European Space Agency’s Swarm mission. Based on the Swarm data, we have developed the Ionospheric Plasma IRregularities (IPIR) product for a global characterisation of ionospheric irregularities along the satellite track at all latitudes. This new Level-2 data product combines complementary datasets from the Swarm satellites: the electron density from the electric field instrument, the GPS data from the onboard GPS receiver, and the magnetic field data from the onboard magnetometers. This can be used as a new tool for global studies of ionospheric irregularities and turbulence.

Download Full-text

Structural characterization of the equatorial F region plasma irregularities in the multifractal context

10.5194/angeo-2019-133 ◽

2019 ◽

Author(s):

Neelakshi Joshi ◽

Reinaldo R. Rosa ◽

Siomel Savio ◽

Esfhan Alam Kherani ◽

Francisco Carlos de Meneses ◽

...

Keyword(s):

Ionospheric Plasma ◽

Fluctuation Analysis ◽

Multifractal Detrended Fluctuation Analysis ◽

Plasma Irregularities ◽

In Situ Data ◽

F Region ◽

Linear Algorithms ◽

Multiplicative Cascade

Abstract. In the emerging ionosphere-space-weather paradigm, investigating dynamical properties of ionospheric plasma irregularities using advanced computational non-linear algorithms is providing new insights into their turbulent-like nature, for instance, the evidence of energy distribution via multiplicative cascade. In this study, we present multifractal analysis of the equatorial F region in situ data obtained from two different experiments performed at Alcântara (2.4° S; 44.4° W), Brazil to explore their scaling structures. First experiment observed several large-medium scale plasma bubbles whereas second experiment observed vertical uplift of the base of F region. Multifractal detrended fluctuation analysis and p-model fit is used to analyze the plasma density fluctuation time series. Result shows presence of multifractality with degree of multifractality 0.53–1.1 with 0.29 &leq; p &leq; 0.4 cascading probability for first experiment. Another experimental data also exhibits multifractality with degree of multifractality 0.27–0.33 with 0.42 &leq; p &leq; 0.44 cascading probability in the ionospheric plasma irregularities. Our results confirm the nonhomogeneous nature of plasma irregularities and characterize the underlying nonhomogeneous multiplicative cascade hypothesis in the ionospheric medium. Differences in terms of scaling and complexity in data belonging to different types of phenomena are also addressed.

Download Full-text

Rocket in situ observation of equatorial plasma irregularities in the region between E and F layers over Brazil

Annales Geophysicae ◽

10.5194/angeo-35-413-2017 ◽

2017 ◽

Vol 35 (3) ◽

pp. 413-422 ◽

Cited By ~ 5

Author(s):

Siomel Savio Odriozola ◽

Francisco Carlos de Meneses Jr. ◽

Polinaya Muralikrishna ◽

Alexandre Alvares Pimenta ◽

Esfhan Alam Kherani

Keyword(s):

Langmuir Probe ◽

In Situ Observation ◽

Very High Frequency ◽

Vhf Radar ◽

Plasma Irregularities ◽

F Region ◽

Vertical Drift ◽

Constant Bias ◽

Wave Patterns

Abstract. A two-stage VS-30 Orion rocket was launched from the equatorial rocket launching station in Alcântara, Brazil, on 8 December 2012 soon after sunset (19:00 LT), carrying a Langmuir probe operating alternately in swept and constant bias modes. At the time of launch, ground equipment operated at equatorial stations showed rapid rise in the base of the F layer, indicating the pre-reversal enhancement of the F region vertical drift and creating ionospheric conditions favorable for the generation of plasma bubbles. Vertical profiles of electron density estimated from Langmuir probe data showed wave patterns and small- and medium-scale plasma irregularities in the valley region (100–300 km) during the rocket upleg and downleg. These irregularities resemble those detected by the very high frequency (VHF) radar installed at Jicamarca and so-called equatorial quasi-periodic echoes. We present evidence suggesting that these observations could be the first detection of this type of irregularity made by instruments onboard a rocket.

Download Full-text

Ionospheric plasma irregularities inside the mid-latitude trough by using Swarm observations

10.5194/egusphere-egu21-7293 ◽

2021 ◽

Author(s):

Yiwen Liu ◽

Chao Xiong ◽

Xin Wan

Keyword(s):

Ionospheric Plasma ◽

Density Fluctuations ◽

Small Scale ◽

Topside Ionosphere ◽

Density Measurements ◽

Plasma Irregularities ◽

Electron Density And Temperature ◽

Swarm Satellite ◽

First Time

<p>The mid-latitude ionospheric trough (MIT) is a well-known feature in the topside ionosphere and plasmasphere. In this report,&#160;we&#160;investigated&#160;the plasma irregularities inside the MIT region&#160;based on the high-resolution (2 Hz) measurements of electron density and temperature from the Swarm satellite. We developed a method to&#160;automatically&#160;identify the mid-latitude trough from Swarm in-situ density measurements, and&#160;the small-scale irregularities inside MIT region can also be well determined by considering appropriate thresholds of&#160;both the relative (&#8710;Ne/Ne) and&#160;absolute (&#8710;Ne) density fluctuations. Further statistics has been performed&#160;based-on the multi-years database of identified MITs and irregularities from Swarm. Finally, we&#160;provided for the first time the seasonal and magnetic local time distributions of irregularities within the MIT region, and the involved plasma instabilities&#160;that cause&#160;the irregularities&#160;at the MIT region have been discussed.</p>

Download Full-text

Structural characterization of the equatorial F region plasma irregularities in the multifractal context

Annales Geophysicae ◽

10.5194/angeo-38-445-2020 ◽

2020 ◽

Vol 38 (2) ◽

pp. 445-456

Author(s):

Neelakshi Joshi ◽

Reinaldo R. Rosa ◽

Siomel Savio ◽

Esfhan Alam Kherani ◽

Francisco Carlos de Meneses ◽

...

Keyword(s):

Large Scale ◽

Ionospheric Plasma ◽

Fluctuation Analysis ◽

Multifractal Detrended Fluctuation Analysis ◽

Plasma Irregularities ◽

In Situ Data ◽

F Region ◽

Multiplicative Cascade

Abstract. In the emerging ionosphere–space–weather paradigm, investigating the dynamical properties of ionospheric plasma irregularities using advanced computational nonlinear algorithms provide new insights into their turbulent-seeming nature, for instance, the evidence of energy distribution via a multiplicative cascade. In this study, we present a multifractal analysis of the equatorial F region in situ data obtained from two different experiments performed at Alcântara (2.4∘ S, 44.4∘ W), Brazil, to explore their scaling structures. The first experiment observed several medium- to large-scale plasma bubbles whereas the second experiment observed vertical uplift of the base of the F region. The multifractal detrended fluctuation analysis and the p-model fit are used to analyze the plasma density fluctuation time series. The result shows the presence of multifractality with degree of multifractality 0.53–0.93 and 0.3≤p≤0.4 cascading probability for the first experiment. Other experimental data also exhibit multifractality with degree of multifractality 0.19–0.27 and 0.42≤p≤0.44 cascading probability in ionospheric plasma irregularities. Our results confirm the nonhomogeneous nature of plasma irregularities and characterize the underlying nonhomogeneous multiplicative cascade hypothesis in the ionospheric medium. Differences in terms of scaling and complexity in the data belonging to different types of phenomena are also addressed.

Download Full-text

In Situ Observation of Catalyzed Gasification of Graphite by Nickel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100097090 ◽

1981 ◽

Vol 39 ◽

pp. 76-77

Author(s):

R. T. K. Baker ◽

R. D. Sherwood

Keyword(s):

Objective Lens ◽

In Situ Observation ◽

Gas Flows ◽

Catalytic Gasification ◽

Television Camera ◽

Viewing Screen ◽

Fuels And Chemicals ◽

Gasification Of Carbon ◽

Transmission Microscope

The catalytic gasification of carbon at high temperature by microscopic size metal particles is of fundamental importance to removal of coke deposits and conversion of refractory hydrocarbons into fuels and chemicals. The reaction of metal/carbon/gas systems can be observed by controlled atmosphere electron microscopy (CAEM) in an 100 KV conventional transmission microscope. In the JEOL gas reaction stage model AGl (Fig. 1) the specimen is positioned over a hole, 200μm diameter, in a platinum heater strip, and is interposed between two apertures, 75μm diameter. The control gas flows across the specimen and exits through these apertures into the specimen chamber. The gas is further confined by two apertures, one in the condenser and one in the objective lens pole pieces, and removed by an auxiliary vacuum pump. The reaction zone is <1 mm thick and is maintained at gas pressure up to 400 Torr and temperature up to 1300<C as measured by a Pt-Pt/Rh 13% thermocouple. Reaction events are observed and recorded on videotape by using a Philips phosphor-television camera located below a hole in the center of the viewing screen. The overall resolution is greater than 2.5 nm.

Download Full-text

In situ observation of the martensitic transformation in (Mg,Y)-PSZ

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100144036 ◽

1986 ◽

Vol 44 ◽

pp. 500-501

Author(s):

R-R. Lee

Keyword(s):

Martensitic Transformation ◽

High Strength ◽

Nucleation And Growth ◽

In Situ Observation ◽

Considerable Potential ◽

Transmission Electron ◽

Structural Applications ◽

Applied Stresses ◽

Kinetics Of

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.

Download Full-text

In situ TEM observations of melting in nanosized eutectic Pb-Cd inclusions embedded in Al

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100167391 ◽

1996 ◽

Vol 54 ◽

pp. 986-987

Author(s):

S. Hagège ◽

U. Dahmen ◽

E. Johnson ◽

A. Johansen ◽

V.S. Tuboltsev

Keyword(s):

Electron Microscope ◽

Melt Spinning ◽

Ternary Alloys ◽

Solid Matrix ◽

Eutectic System ◽

In Situ Tem ◽

In Situ Observation ◽

Orientation Relationships ◽

Transmission Electron

Small particles of a low-melting phase embedded in a solid matrix with a higher melting point offer the possibility of studying the mechanisms of melting and solidification directly by in-situ observation in a transmission electron microscope. Previous studies of Pb, Cd and other low-melting inclusions embedded in an Al matrix have shown well-defined orientation relationships, strongly faceted shapes, and an unusual size-dependent superheating before melting.[e.g. 1,2].In the present study we have examined the shapes and thermal behavior of eutectic Pb-Cd inclusions in Al. Pb and Cd form a simple eutectic system with each other, but both elements are insoluble in solid Al. Ternary alloys of Al (Pb,Cd) were prepared from high purity elements by melt spinning or by sequential ion implantation of the two alloying additions to achieve a total alloying addition of up to lat%. TEM observations were made using a heating stage in a 200kV electron microscope equipped with a video system for recording dynamic behavior.

Download Full-text