This presentation illustrates the recent results obtained in the context of scientific ESA Swarm projects. The project &#8220;Swarm data quality Investigation of Field-Aligned Current products, Ionosphere, and Thermosphere system&#8221; (SIFACIT) has been recently extended in order to achieve two additional objectives: To provide to users an open-source program package to estimate Field Aligned Current (FAC) density and quality indicators, using single- and multi-s/c methods from Swarm data; To study the Joule heating of the ionosphere&#8211;thermosphere system on multiple scales, using Swarm data, together with conjugate ground information and simulations.The other project illustrated here is EPHEMERIS (nEw sPace weatHER inforMation Exploited from the SwaRm observatIonS). This project is investigating the Midlatitude Ionospheric Trough (MIT) with Swarm data, and will also develop a new MIT Swarm data product based on Swarm L1b Langmuir Probe (LP) data. The second part of the project will develop a quasi-real-time intermittency index (IMI) for the detection of ionosphere plasma irregularities along the Swarm orbit, which can be responsible for errors and loss of lock in GPS signals. A statistical comparison of the IMI index with GPS signal from ground based receivers will be performed, in order to identify the ionospheric irregularities at Swarm altitude responsible for scintillations in GPS signals.

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Quasi real-time monitoring of the ionosphere plasma irregularities by the records of the Swarm mission

10.5194/egusphere-egu21-16093 ◽

2021 ◽

Author(s):

Peter Kovacs ◽

Balazs Heilig

Keyword(s):

Magnetic Field ◽

Temporal Distribution ◽

Typical Feature ◽

Low Earth Orbit ◽

Space Environment ◽

Signal Loss ◽

Plasma Bubble ◽

Plasma Irregularities ◽

Ionosphere Plasma ◽

Swarm Mission

The magnetic and plasma observations of Low-Earth orbit (LEO) space missions represent not only the dynamical state of the ionosphere but also the physical variations of its electromagnetically connected surroundings, i.e. of the plasmasphere and magnetosphere, as well as of their driver, the solar wind. The monitoring of the ionosphere plasma variables is therefore a big asset for the study of our space environment in broad spatial region. Within the framework of the EPHEMERIS project supported by ESA, we aim at investigating two ionosphere phenomena that exhibit close relationship to global physical processes and space weather activity. We use the magnetic and plasma records of the LEO Swarm mission. First, we investigate the temporal and spatial occurrences of the mid-latitude ionosphere trough (MIT), a typical feature of the topside sub-auroral ionosphere appearing as a few degree wide depleted zone, where electron density (Ne) drops by orders of magnitude. It is shown that the locations of MITs are excellent proxies for the detection of the plasmapause position as well as of the equatorward edge of the auroral oval. Secondly, we monitor the irregular fluctuations of the magnetic field along the Swarm orbits via their intermittent behaviour. A new index called intermittency index (IMI) is introduced for the quantitative exemplification of the spatial and temporal distribution of irregular variations at the Swarm spacecraft altitudes. The paper focuses on the introduction of the methodology of IMI time-series compilation. Since IMIs are deduced via a statistical approach, we use the 50 Hz sampling frequency magnetic field records of the mission. We show that most frequently, the ionosphere magnetic field irregularities occur at low-latitudes, about the dip equator and at high latitudes, around the auroral region. It is conjectured that the equatorial events are the results of equatorial spread F (ESF) or equatorial plasma bubble (EPB) phenomena, while the auroral irregularities are related to field-aligned currents (FAC). The ionosphere plasma irregularities may result in the distortion or loss of GPS signals. Therefore our analysis also concerns the investigation of the correlation between observed intermittent events in the ionosphere and contemporary GPS signal loss events and scintillations detected both by on-board Swarm GPS receivers and ground GNSS stations.

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LINDA – the Astrid-2 Langmuir probe instrument

Annales Geophysicae ◽

10.5194/angeo-19-601-2001 ◽

2001 ◽

Vol 19 (6) ◽

pp. 601-610 ◽

Cited By ~ 8

Author(s):

B. Holback ◽

Å. Jacksén ◽

L. Åhlén ◽

S.-E. Jansson ◽

A. I. Eriksson ◽

...

Keyword(s):

Langmuir Probe ◽

Sampling Rate ◽

Plasma Temperature ◽

Plasma Waves ◽

Ground Contact ◽

Spatial Structures ◽

Ionosphere Plasma ◽

High Sampling Rate ◽

Temporal Structures ◽

Instruments And Techniques

Abstract. The Swedish micro-satellite Astrid-2, designed for studies in magnetosperic physics, was launched into orbit on 10 December 1998 from the Russian cosmodrome Plesetsk. It was injected into a circular orbit at 1000 km and at 83 degrees inclination. The satellite carried, among other instruments, a double Langmuir Probe instrument called LINDA (Langmuir INterferometer and Density instrument for Astrid-2). The scientific goals of this instrument, as well as the technical design and possible modes of operation, are described. LINDA consists of two lightweight deployable boom systems, each carrying a small spherical probe. With these probes, separated by 2.9 meters, and in combination with a high sampling rate, it was possible to discriminate temporal structures (waves) from spatial structures. An on-board memory made it possible to collect data also at times when there was no ground contact. Plasma density and electron temperature data from all magnetic latitudes and for all seasons have been collected.Key words. Ionosphere (plasma temperature and density; plasma waves and instabilities; instruments and techniques)

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Transient production of F-region irregularities associated with TCV passage

Annales Geophysicae ◽

10.5194/angeo-21-1531-2003 ◽

2003 ◽

Vol 21 (7) ◽

pp. 1531-1541 ◽

Cited By ~ 4

Author(s):

R. Kataoka ◽

H. Fukunishi ◽

K. Hosokawa ◽

H. Fujiwara ◽

A. S. Yukimatu ◽

...

Keyword(s):

Electric Fields ◽

Current System ◽

Rapid Evolution ◽

Three Dimensional ◽

Leading Edge ◽

Spectral Width ◽

Plasma Convection ◽

Plasma Irregularities ◽

F Region ◽

Field Aligned Current

Abstract. Transient production of F-region plasma irregularities due to traveling convection vortices (TCVs) was investigated using the Super Dual Auroral Radar Network (SuperDARN) combined with ground magnetometer networks and the POLAR ultraviolet imager. We selected two large-amplitude (100–200 nT) TCV events that occurred on 22 May 1996 and 24 July 1996. It is found that the TCV-associated HF backscatter arises in blobs with spatial scale of a few hundreds km. They traveled following tailward bulk motion of the TCV across the three fields-of-view of the SuperDARN HF radars in the prenoon sector. The spectra in the blobs showed unidirectional Doppler velocities of typically 400–600 m/s, with flow directions away from the radar. These unidirectional velocities correspond to the poleward and/or eastward convective flow near the leading edge of upward field-aligned current. The backscatter blobs overlapped the poleward and westward part of the TCV-related transient aurora. It is likely that the transient backscatter blobs are produced by the three-dimensional gradient drift instabilities in the three-dimensional current system of the TCV. In this case, nonlinear rapid evolution of irregularities would occur in the upward field-aligned current region. The spectral width of the backscatter blob is typically distributed between 50 and 300 m/s, but sometimes it is over 400 m/s. This suggests that the temporal broad spectra over 400 m/s are produced by Pc1–2 bursts, while the background spectral width of 50–300 m/s are produced by the velocity gradient structure of convection vortices themselves.Key words. Ionosphere (Electric fields and currents; Ionospheric irregularities; Plasma convection)

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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.

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Nonlinear Dynamics of a Fluid–Structure Coupling Model for Vortex-Induced Vibration

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455419500718 ◽

2019 ◽

Vol 19 (07) ◽

pp. 1950071 ◽

Cited By ~ 5

Author(s):

Jie Chen ◽

Qiu-Sheng Li

Keyword(s):

Vortex Shedding ◽

Multiple Scales ◽

Coupled Model ◽

Coupling Model ◽

Motion Equation ◽

Multiple Scales Method ◽

Modulation Equation ◽

Fluid Structure ◽

Vortex Induced Vibration ◽

Lock In

This paper presents a fluid–structure coupling model to investigate the vortex-induced vibration of a circular cylinder subjected to a uniform cross-flow. A modified van der Pol nonlinear equation is employed to represent the fluctuating nature of vortex shedding. The wake oscillator is coupled with the motion equation of the cylinder by applying coupling terms in modeling the fluid–structure interaction. The transient responses of the fluid–structure coupled model are presented and discussed by numerical simulations. The results demonstrate the main features of the vortex-induced vibration, such as lock-in phenomenon, i.e. resonant oscillation of the cylinder occurs when the vortex shedding frequency is near to the natural frequency of the cylinder. The resonant responses of the fluid–structure coupled model in the lock-in region are determined by the multiple scales method. The accuracy of the asymptotic solution by the multiple scales method is verified by comparing with the numerical solution from the motion equation. The effects of different parameters on the steady state amplitude of oscillation are investigated for a given set of parameters. Frequency–response curves obtained from the modulation equation demonstrate the existence of jump phenomena.

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Diurnal variations in the spectrum of lower-ionosphere plasma irregularities

Kinematics and Physics of Celestial Bodies ◽

10.3103/s0884591307020055 ◽

2007 ◽

Vol 23 (2) ◽

pp. 73-76

Author(s):

Yu. V. Kyz’yurov

Keyword(s):

Lower Ionosphere ◽

Diurnal Variations ◽

Plasma Irregularities ◽

Ionosphere Plasma

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Seti Space Missions

International Astronomical Union Colloquium ◽

10.1017/s0252921100015372 ◽

1997 ◽

Vol 161 ◽

pp. 761-776 ◽

Cited By ~ 1

Author(s):

Claudio Maccone

Keyword(s):

Electromagnetic Waves ◽

Space Missions ◽

Gravitational Lens ◽

The Sun ◽

Space Antenna ◽

Focal Distance ◽

Large Space ◽

The Earth ◽

Space Antennas ◽

New Space

AbstractSETI from space is currently envisaged in three ways: i) by large space antennas orbiting the Earth that could be used for both VLBI and SETI (VSOP and RadioAstron missions), ii) by a radiotelescope inside the Saha far side Moon crater and an Earth-link antenna on the Mare Smythii near side plain. Such SETIMOON mission would require no astronaut work since a Tether, deployed in Moon orbit until the two antennas landed softly, would also be the cable connecting them. Alternatively, a data relay satellite orbiting the Earth-Moon Lagrangian pointL2would avoid the Earthlink antenna, iii) by a large space antenna put at the foci of the Sun gravitational lens: 1) for electromagnetic waves, the minimal focal distance is 550 Astronomical Units (AU) or 14 times beyond Pluto. One could use the huge radio magnifications of sources aligned to the Sun and spacecraft; 2) for gravitational waves and neutrinos, the focus lies between 22.45 and 29.59 AU (Uranus and Neptune orbits), with a flight time of less than 30 years. Two new space missions, of SETI interest if ET’s use neutrinos for communications, are proposed.

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