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

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

<p>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.</p>

Recent achievements from the Swarm mission on the low latitude space environment and combinations with other satellite missions

2020 ◽  
Author(s):  
Claudia Stolle ◽  
Juan Rodríguez-Zuluaga ◽  
Chao Xiong ◽  
Yosuke Yamazaki ◽  
Guram Kervalishvili ◽  
...  
Keyword(s):  
Equatorial Electrojet ◽  
Space Environment ◽  
Space Technology ◽  
Low Latitude ◽  
Plasma Irregularities ◽  
Multiple Parameters ◽  
The Earth ◽  
Gps Scintillation ◽  
Low Latitude Ionosphere ◽  
Swarm Mission

<p>The Swarm three-satellite constellation mission provides high resolution and high-quality observations of the Earth’s magnetic field and of multiple parameters of the ionosphere, which lead to new knowledge on the Earth’s interior and space environment and help to investigate space weather effects on space technology. Several findings would otherwise not have been possible and demonstrate that missions like Swarm are indispensable for Earth and space exploration. In addition, aspects of longterm variations or enhanced understanding in temporal and spatial resolution on regional scales could be gained in combination with other missions. This presentation  focuses on recent achievements on the low latitude ionosphere. Examples include an empirical model of the occurrence of post-sunset equatorial plasma irregularities derived in combination with ten years of CHAMP geomagnetic data, an enhanced description of the Swarm irregularity observations together with regional maps of the South Atlantic ionosphere from GOLD, and the identification of differing GPS scintillation characteristics evoked by the irregularities in comparison with the lower orbit GOCE data. Equatorial electrojet and plasma data from Swarm also helped to empirically prove that Antarctic sudden stratospheric warming events, such as in September 2019, couple to the low latitude ionosphere through modified planetary waves.</p>

scholarly journals The Effect of Low Earth Orbit Atomic Oxygen Exposure on Phenylphosphine Oxide-Containing Polymers

2000 ◽  
Vol 12 (1) ◽  
pp. 43-52 ◽  
Author(s):  
John W Connell
Keyword(s):  
Thin Film ◽  
Atomic Oxygen ◽  
Low Earth Orbit ◽  
Space Environment ◽  
Earth Orbit ◽  
Cooperative Effort ◽  
Flight Experiment ◽  
Oxygen Exposure ◽  
Atomic Oxygen Exposure ◽  
Phenylphosphine Oxide

Thin films of phenylphosphine oxide-containing polymers were exposed to low Earth orbit aboard a space shuttle flight (STS-85) as part of flight experiment designated Evaluation of Space Environment and Effects on Materials (ESEM). This flight experiment was a cooperative effort between the NASA Langley Research Center (LaRC) and the National Space Development Agency of Japan (NASDA). The thin-film samples described herein were part of an atomic oxygen exposure (AOE) experiment and were exposed to primarily atomic oxygen (∼1×1019 atoms cm−2). The thin-film samples consisted of three phosphine oxide-containing polymers (arylene ether, benzimidazole and imide). Based on post-flight analyses using atomic force microscopy, x-ray photo-electron spectroscopy and weight loss data, it was found that the exposure of these materials to atomic oxygen (AO) produces a phosphorus oxide layer on the surface of the samples. Earlier work has shown that this layer provides a barrier towards further attack by AO. Consequently, these materials do not exhibit linear erosion rates which is in contrast with most organic polymers. Qualitatively, the results obtained from these analyses compare favourably with those obtained from samples exposed to AO and/or an oxygen plasma in ground-based exposure experiments. The results of the low Earth orbit AO exposure on these materials will be compared with those of ground-based exposure to AO.

scholarly journals The affect of the space environment on the survival ofHalorubrum chaoviatorandSynechococcus(Nägeli): data from the Space Experiment OSMO on EXPOSE-R

2014 ◽  
Vol 14 (1) ◽  
pp. 123-128 ◽  
Author(s):  
R. L. Mancinelli
Keyword(s):  
Survival Rate ◽  
Uv Radiation ◽  
Molecular Probes ◽  
Low Earth Orbit ◽  
Space Environment ◽  
Dust Particles ◽  
Most Probable Number ◽  
Earth Orbit ◽  
Probable Number ◽  
Space Vacuum

AbstractWe have shown using ESA's Biopan facility flown in Earth orbit that when exposed to the space environment for 2 weeks the survival rate ofSynechococcus(Nägeli), a halophilic cyanobacterium isolated from the evaporitic gypsum–halite crusts that form along the marine intertidal, andHalorubrum chaoviatora member of the Halobacteriaceae isolated from an evaporitic NaCl crystal obtained from a salt evaporation pond, were higher than all other test organisms exceptBacillusspores. These results led to the EXPOSE-R mission to extend and refine these experiments as part of the experimental package for the external platform space exposure facility on the ISS. The experiment was flown in February 2009 and the organisms were exposed to low-Earth orbit for nearly 2 years. Samples were either exposed to solar ultraviolet (UV)-radiation (λ > 110 nm or λ > 200 nm, cosmic radiation (dosage range 225–320 mGy), or kept in darkness shielded from solar UV-radiation. Half of each of the UV-radiation exposed samples and dark samples were exposed to space vacuum and half kept at 105pascals in argon. Duplicate samples were kept in the laboratory to serve as unexposed controls. Ground simulation control experiments were also performed. After retrieval, organism viability was tested using Molecular Probes Live–Dead Bac-Lite stain and by their reproduction capability. Samples kept in the dark, but exposed to space vacuum had a 90 ± 5% survival rate compared to the ground controls. Samples exposed to full UV-radiation for over a year were bleached and although results from Molecular Probes Live–Dead stain suggested ~10% survival, the data indicate that no survival was detected using cell growth and division using the most probable number method. Those samples exposed to attenuated UV-radiation exhibited limited survival. Results from of this study are relevant to understanding adaptation and evolution of life, the future of life beyond earth, the potential for interplanetary transfer of viable microbes via meteorites and dust particles as well as spacecraft, and the physiology of halophiles.

scholarly journals A simulation study investigating potential diffusion-based MRI signatures of microstrokes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rafat Damseh ◽  
Yuankang Lu ◽  
Xuecong Lu ◽  
Cong Zhang ◽  
Paul J. Marchand ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Statistical Power ◽  
Barrel Cortex ◽  
Signal Loss ◽  
Nuclear Spins ◽  
Directional Diffusion ◽  
Ischemic Tissue ◽  
Significant Difference ◽  
Before And After ◽  
Experimental Validations

AbstractRecent studies suggested that cerebrovascular micro-occlusions, i.e. microstokes, could lead to ischemic tissue infarctions and cognitive deficits. Due to their small size, identifying measurable biomarkers of these microvascular lesions remains a major challenge. This work aims to simulate potential MRI signatures combining arterial spin labeling (ASL) and multi-directional diffusion-weighted imaging (DWI). Driving our hypothesis are recent observations demonstrating a radial reorientation of microvasculature around the micro-infarction locus during recovery in mice. Synthetic capillary beds, randomly- and radially-oriented, and optical coherence tomography (OCT) angiograms, acquired in the barrel cortex of mice (n = 5) before and after inducing targeted photothrombosis, were analyzed. Computational vascular graphs combined with a 3D Monte-Carlo simulator were used to characterize the magnetic resonance (MR) response, encompassing the effects of magnetic field perturbations caused by deoxyhemoglobin, and the advection and diffusion of the nuclear spins. We quantified the minimal intravoxel signal loss ratio when applying multiple gradient directions, at varying sequence parameters with and without ASL. With ASL, our results demonstrate a significant difference (p < 0.05) between the signal-ratios computed at baseline and 3 weeks after photothrombosis. The statistical power further increased (p < 0.005) using angiograms measured at week 4. Without ASL, no reliable signal change was found. We found that higher ratios, and accordingly improved significance, were achieved at lower magnetic field strengths (e.g., B0 = 3T) and shorter echo time TE (< 16 ms). Our simulations suggest that microstrokes might be characterized through ASL-DWI sequence, providing necessary insights for posterior experimental validations, and ultimately, future translational trials.

scholarly journals Central polar cap convection response to short duration southward Interplanetary Magnetic Field

2000 ◽  
Vol 18 (8) ◽  
pp. 887-896 ◽  
Author(s):  
P. T. Jayachandran ◽  
J. W. MacDougall
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
Short Duration ◽  
Initial Response ◽  
Plasma Convection ◽  
Polar Cap ◽  
Ionosphere Plasma ◽  
Rapid Transition ◽  
Convection Speed ◽  
A Chain

Abstract. Central polar cap convection changes associated with southward turnings of the Interplanetary Magnetic Field (IMF) are studied using a chain of Canadian Advanced Digital Ionosondes (CADI) in the northern polar cap. A study of 32 short duration (~1 h) southward IMF transition events found a three stage response: (1) initial response to a southward transition is near simultaneous for the entire polar cap; (2) the peak of the convection speed (attributed to the maximum merging electric field) propagates poleward from the ionospheric footprint of the merging region; and (3) if the change in IMF is rapid enough, then a step in convection appears to start at the cusp and then propagates antisunward over the polar cap with the velocity of the maximum convection. On the nightside, a substorm onset is observed at about the time when the step increase in convection (associated with the rapid transition of IMF) arrives at the polar cap boundary.Key words: Ionosphere (plasma convection; polar ionosphere) - Magnetospheric physics (solar wind - magnetosphere interaction)

scholarly journals Simulation study of the plasma-brake effect

2014 ◽  
Vol 32 (10) ◽  
pp. 1207-1216 ◽  
Author(s):  
P. Janhunen
Keyword(s):  
Magnetic Field ◽  
High Performance ◽  
Ionospheric Plasma ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Breaking Force ◽  
Field Orientation ◽  
Particle In Cell ◽  
Leo Satellite ◽  
The Magnetic Field

Abstract. Plasma brake is a thin, negatively biased tether that has been proposed as an efficient concept for deorbiting satellites and debris objects from low Earth orbit. We simulate the interaction with the ionospheric plasma ram flow with the plasma-brake tether by a high-performance electrostatic particle in cell code to evaluate the thrust. The tether is assumed to be perpendicular to the flow. We perform runs for different tether voltage, magnetic-field orientation and plasma-ion mass. We show that a simple analytical thrust formula reproduces most of the simulation results well. The interaction with the tether and the plasma flow is laminar (i.e. smooth and not turbulent) when the magnetic field is perpendicular to the tether and the flow. If the magnetic field is parallel to the tether, the behaviour is unstable and thrust is reduced by a modest factor. The case in which the magnetic field is aligned with the flow can also be unstable, but does not result in notable thrust reduction. We also correct an error in an earlier reference. According to the simulations, the predicted thrust of the plasma brake is large enough to make the method promising for low-Earth-orbit (LEO) satellite deorbiting. As a numerical example, we estimate that a 5 km long plasma-brake tether weighing 0.055 kg could produce 0.43 mN breaking force, which is enough to reduce the orbital altitude of a 260 kg object mass by 100 km over 1 year.

scholarly journals Modern radar techniques and the hazard of meteoroids to space platforms

1998 ◽  
Vol 41 (5-6) ◽  
Author(s):  
G. Cevolani
Keyword(s):  
Parent Body ◽  
Low Earth Orbit ◽  
Space Environment ◽  
Meteoroid Streams ◽  
Storm Activity ◽  
Plasma Generation ◽  
Near Earth Space ◽  
Space Objects ◽  
Very High ◽  
Perihelion Passage

Modern radar techniques, and in particular ground based radars, are a powerful tool to observe space objects (natural meteoroids and artificial space debris) on account of their all-weather and day-and-night performance. Natural meteoroids are an important component of the near-Earth space environment and represent a potential risk for all Earth-orbiting space platforms, which could significantly increase in coincidence of enhanced (outburst or storm) activity of meteoroid streams. A review of the currently active meteoroid streams suggests that a few streams have shown a quasi-periodic outburst activity in the two last centuries and may even undergo a storm activity in the next few years. The Leonids, the most intense of meteor showers, present a potentially serious damage to spacecraft in November of 1998 and 1999, after the perihelion passage of the parent body. Impact probability values of storm meteoroids on space platforms in Low Earth Orbit (LEO) were calculated using the data recorded during systematic observational campaigns carried out by the FS radar facility Bologna-Lecce in Italy. Meteoroid flux predictions and directionality, and investigation on impact parameters at very high velocities (up to 71 km/s) for penetration, charge production and plasma generation, are relevant aspects to develop strategies for safe deployment of the near Earrth-orbiting space platforms.

scholarly journals Magnetometer in-flight offset accuracy for the BepiColombo spacecraft

2020 ◽  
Vol 38 (4) ◽  
pp. 823-832 ◽  
Author(s):  
Daniel Schmid ◽  
Ferdinand Plaschke ◽  
Yasuhito Narita ◽  
Daniel Heyner ◽  
Johannes Z. D. Mieth ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Field Measurements ◽  
Observation Time ◽  
Space Environment ◽  
Method Performance ◽  
Mode Method ◽  
Magnetometer Data ◽  
Mirror Mode ◽  
Fluctuation Method

Abstract. Recently the two-spacecraft mission BepiColombo launched to explore the plasma and magnetic field environment of Mercury. Both spacecraft, the Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MMO, also referred to as Mio), are equipped with fluxgate magnetometers, which have proven to be well-suited to measure the magnetic field in space with high precision. Nevertheless, accurate magnetic field measurements require proper in-flight calibration. In particular the magnetometer offset, which relates relative fluxgate readings into an absolute value, needs to be determined with high accuracy. Usually, the offsets are evaluated from observations of Alfvénic fluctuations in the pristine solar wind, if those are available. An alternative offset determination method, which is based on the observation of highly compressional fluctuations instead of incompressible Alfvénic fluctuations, is the so-called mirror mode technique. To evaluate the method performance in the Hermean environment, we analyze four years of MESSENGER (MErcury Surface, Space ENvironment, GEophysics and Ranging) magnetometer data, which are calibrated by the Alfvénic fluctuation method, and compare it with the accuracy and error of the offsets determined by the mirror mode method in different plasma environments around Mercury. We show that the mirror mode method yields the same offset estimates and thereby confirms its applicability. Furthermore, we evaluate the spacecraft observation time within different regions necessary to obtain reliable offset estimates. Although the lowest percentage of strong compressional fluctuations are observed in the solar wind, this region is most suitable for an accurate offset determination with the mirror mode method. 132 h of solar wind data are sufficient to determine the offset to within 0.5 nT, while thousands of hours are necessary to reach this accuracy in the magnetosheath or within the magnetosphere. We conclude that in the solar wind the mirror mode method might be a good complementary approach to the Alfvénic fluctuation method to determine the (spin-axis) offset of the Mio magnetometer.

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