Indices of geomagnetic activity derived from space-born magnetic data from the Swarm mission

2021 ◽  
Author(s):  
Constantinos Papadimitriou ◽  
Georgios Balasis ◽  
Adamantia Zoe Boutsi ◽  
Ioannis A. Daglis ◽  
Omiros Giannakis ◽  
...  
Keyword(s):  
Geomagnetic Activity ◽  
Magnetic Measurements ◽  
Low Earth Orbit ◽  
Magnetic Data ◽  
Satellite Mission ◽  
The Earth ◽  
Terrestrial Magnetosphere ◽  
First Results ◽  
Monitoring And Forecasting ◽  
Swarm Mission

<p>Ground based indices, such as the Dst and AE, have been used for decades to describe the interplay of the terrestrial magnetosphere with the solar wind and provide quantifiable indications of the state of geomagnetic activity in general. These indices have been traditionally derived from ground based observations from magnetometer stations all around the Earth. In the last 7 years though, the highly successful satellite mission Swarm has provided the scientific community with an abundance of high quality magnetic measurements at Low Earth Orbit, which can be used to produce the space-based counterparts of these indices, such the Swarm-Dst and Swarm-AE Indices. In this work, we present the first results from this endeavour, with comparisons against traditionally used parameters, and postulate on the possible usefulness of these Swarm based products for space weather monitoring and forecasting.</p>

scholarly journals The Ad Hoc Back-End of the BIRALET Radar to Measure Slant-Range and Doppler Shift of Resident Space Objects

Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 577
Author(s):  
Luca Schirru ◽  
Tonino Pisanu ◽  
Angelo Podda
Keyword(s):  
Doppler Shift ◽  
Space Debris ◽  
Ad Hoc ◽  
Low Earth Orbit ◽  
Slant Range ◽  
Radar Systems ◽  
The Earth ◽  
Space Objects ◽  
Resident Space Objects ◽  
Potential Issue

Space debris is a term for all human-made objects orbiting the Earth or reentering the atmosphere. The population of space debris is continuously growing and it represents a potential issue for active satellites and spacecraft. New collisions and fragmentation could exponentially increase the amount of debris and so the level of risk represented by these objects. The principal technique used for the debris monitoring, in the Low Earth Orbit (LEO) between 200 km and 2000 km of altitude, is based on radar systems. The BIRALET system represents one of the main Italian radars involved in resident space objects observations. It is a bi-static radar, which operates in the P-band at 410–415 MHz, that uses the Sardinia Radio Telescope as receiver. In this paper, a detailed description of the new ad hoc back-end developed for the BIRALET radar, with the aim to perform slant-range and Doppler shift measurements, is presented. The new system was successfully tested in several validation measurement campaigns, the results of which are reported and discussed.

scholarly journals Radial variation of whistler-mode chorus: first results from the STAFF/DWP instrument on board the Double Star TC-1 spacecraft

2005 ◽  
Vol 23 (8) ◽  
pp. 2937-2942 ◽  
Author(s):  
O. Santolík ◽  
E. Macúšová ◽  
K. H. Yearby ◽  
N. Cornilleau-Wehrlin ◽  
H. StC. K. Alleyne
Keyword(s):  
Cyclotron Frequency ◽  
Power Spectra ◽  
Double Star ◽  
Electron Cyclotron ◽  
Radial Variation ◽  
Whistler Mode ◽  
Electron Cyclotron Frequency ◽  
The Earth ◽  
First Results ◽  
Initial Results

Abstract. We use the first measurements of the STAFF/DWP instrument on the Double Star TC-1 spacecraft to investigate whistler-mode chorus. We present initial results of a systematic study on radial variation of dawn chorus. The chorus events show an increased intensity at L parameter above 6. This is important for the possible explanation of intensifications of chorus, which were previously observed closer to the Earth at higher latitudes. Our results also indicate that the upper band of chorus at frequencies above one-half of the electron cyclotron frequency disappears for L above 8. The lower band of chorus is observed at frequencies below 0.4 of the electron cyclotron frequency up to L of 11-12. The maxima of the chorus power spectra are found at slightly lower frequencies compared to previous studies. We do not observe any distinct evolution of the position of the chorus frequency band as a function of L. More data of the TC-1 spacecraft are needed to verify these initial results and to increase the MLT coverage.

scholarly journals From GPS Receiver to GNSS Reflectometry Payload Development for the Triton Satellite Mission

2021 ◽  
Vol 13 (5) ◽  
pp. 999
Author(s):  
Yung-Fu Tsai ◽  
Wen-Hao Yeh ◽  
Jyh-Ching Juang ◽  
Dian-Syuan Yang ◽  
Chen-Tsung Lin
Keyword(s):  
Satellite System ◽  
Low Earth Orbit ◽  
Export Control ◽  
Navigation Systems ◽  
Gps Receiver ◽  
Design Development ◽  
Satellite Mission ◽  
Essential Components ◽  
Gnss Reflectometry ◽  
Global Navigation Satellite

The global positioning system (GPS) receiver has been one of the most important navigation systems for more than two decades. Although the GPS system was originally designed for near-Earth navigation, currently it is widely used in highly dynamic environments (such as low Earth orbit (LEO)). A space-capable GPS receiver (GPSR) is capable of providing timing and navigation information for spacecraft to determine the orbit and synchronize the onboard timing; therefore, it is one of the essential components of modern spacecraft. However, a space-grade GPSR is technology-sensitive and under export control. In order to overcome export control, the National Space Organization (NSPO) in Taiwan completed the development of a self-reliant space-grade GPSR in 2014. The NSPO GPSR, built in-house, has passed its qualification tests and is ready to fly onboard the Triton satellite. In addition to providing navigation, the GPS/global navigation satellite system (GNSS) is facilitated to many remote sensing missions, such as GNSS radio occultation (GNSS-RO) and GNSS reflectometry (GNSS-R). Based on the design of the NSPO GPSR, the NSPO is actively engaged in the development of the Triton program (a GNSS reflectometry mission). In a GNSS-R mission, the reflected signals are processed to form delay Doppler maps (DDMs) so that various properties (including ocean surface roughness, vegetation, soil moisture, and so on) can be retrieved. This paper describes not only the development of the NSPO GPSR but also the design, development, and special features of the Triton’s GNSS-R mission. Moreover, in order to verify the NSPO GNSS-R receiver, ground/flight tests are deemed essential. Then, data analyses of the airborne GNSS-R tests are presented in this paper.

Data Fusion of Total Solar Irradiance Composite Time Series Using 40 years of Satellite Measurements: First Results 

2021 ◽  
Author(s):  
Jean-Philippe Montillet ◽  
Wolfgang Finsterle ◽  
Werner Schmutz ◽  
Margit Haberreiter ◽  
Rok Sikonja
Keyword(s):  
Time Series ◽  
Data Fusion ◽  
Solar Irradiance ◽  
Total Solar Irradiance ◽  
Maunder Minimum ◽  
The Sun ◽  
Climate Reconstructions ◽  
The Earth ◽  
First Results ◽  
The Difference

<p><span>Since the late 70’s, successive satellite missions have been monitoring the sun’s activity, recording total solar irradiance observations. These measurements are important to estimate the Earth’s energy imbalance, </span><span>i.e. the difference of energy absorbed and emitted by our planet. Climate modelers need the solar forcing time series in their models in order to study the influence of the Sun on the Earth’s climate. With this amount of TSI data, solar irradiance reconstruction models  can be better validated which can also improve studies looking at past climate reconstructions (e.g., Maunder minimum). V</span><span>arious algorithms have been proposed in the last decade to merge the various TSI measurements over the 40 years of recording period. We have developed a new statistical algorithm based on data fusion.  The stochastic noise processes of the measurements are modeled via a dual kernel including white and coloured noise.  We show our first results and compare it with previous releases (PMOD,ACRIM, ... ). </span></p>

NOVEL MAGNETIC PROPERTIES IN MULTI-WALLED CARBON NANOTUBE MATS: CONSISTENT WITH THE PARAMAGNETIC MEISSNER EFFECT DUE TO ULTRAHIGH-TEMPERATURE SUPERCONDUCTIVITY

2009 ◽  
Vol 23 (20n21) ◽  
pp. 4285-4296 ◽  
Author(s):  
GUO-MENG ZHAO ◽  
PIEDER BEELI
Keyword(s):  
Carbon Nanotube ◽  
Saturation Magnetization ◽  
Magnetic Measurements ◽  
Meissner Effect ◽  
Magnetic Data ◽  
Ferromagnetic Transition ◽  
Measured Concentration ◽  
Paramagnetic Meissner Effect ◽  
Multi Walled Carbon Nanotube ◽  
Ultrahigh Temperature

We report magnetic measurements up to 1200 K on iron-contaminated multi-walled carbon nanotube mats with a Quantum Design vibrating sample magnetometer. Extensive magnetic data consistently show a ferrromagnetic transition at about 1000 K and a ferromagnetic-like transition at about 1275 K. The ferromagnetic transition at about 1000 K is associated with an Fe impurity phase and its saturation magnetization is in quantitative agreement with the Fe concentration measured by an inductively coupled plasma mass spectrometer. On the other hand, the saturation magnetization for the ferromagnetic-like phase (at 1275 K) is about four orders of magnitude larger than that expected from the measured concentration of Co or CoFe . We show that this ultrahigh-temperature ferromagnetic-like behavior cannot be explained by ferromagnetism of any Fe -carbon phases, carbon-based phases, or magnetic impurities, but is consistent with the paramagnetic Meissner effect (orbital ferromagnetism) due to the existence of π Josephson junctions in a granular superconductor.

Surface Effects on the Magnetic Behavior of Nanocrystalline Nickel Ferrites: The Effect of Surface Roughness and Dilution

2005 ◽  
Vol 877 ◽  
Author(s):  
H. Nathani ◽  
R.D.K. Misra ◽  
W.F. Egelhoff
Keyword(s):  
Surface Roughness ◽  
Nickel Ferrite ◽  
Magnetic Measurements ◽  
Magnetic Behavior ◽  
Magnetic Data ◽  
Zero Field ◽  
Nanocrystalline Nickel ◽  
Polyethylene Matrix ◽  
Dilution Effects ◽  
Field Cooling

AbstractThe paper describes the surface roughness and dilution effects on the magnetic behavior of nanocrystalline nickel ferrites studied by SQUID magnetometer. Two different kinds of measurements were performed: (a) zero-field cooling (ZFC) and field cooling (FC) magnetization versus temperature and (b) magnetization as a function of the applied field. The analysis of magnetic measurements indicate that while the superparamagnetic behavior is retained by nanocrystalline ferrites of different surface roughness (0.8-1.8 nm) at 300K, the hysteresis loop at 2K becomes non-squared and the coercivity increases with increase in surface roughness. This behavior is discussed in terms of broken bonds and degree of surface spin disorder. In diluted dispersion systems containing 10-40% nickel ferrite in a polyethylene matrix, the interparticle attractions continue to be dominant even when the concentration of nickel ferrite is 10 wt.% in the diluted system. The general magnetic behavior of diluted dispersion system is similar to the undiluted system; however, coercivity, remanence, and saturation magnetization are altered. These changes in the magnetic data are ascribed to magnetization interactions that encourage flux closure configuration.

Global Networking and the Contrapuntal Node: The Project Mercury Earth Station in Zanzibar, 1959-64

2020 ◽  
Vol 11 (2020) ◽  
Author(s):  
Lisa Parks
Keyword(s):  
Satellite Mission ◽  
Earth Station ◽  
The Earth ◽  
The Us ◽  
Us Government

In 1960, the US government and British protectorate of Zanzibar signed an agreement that allowed US contractors working for the National Aeronautics and Space Administration (NASA) to build an earth station that would support Project Mercury, the first manned US satellite mission. This article focuses on the development of the Project Mercury earth station in Zanzibar during 1959-1964. To historicize the earth station’s establishment, the focus lies on the geopolitical and sociotechnical relations that resulted in the Zanzibar station.

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>

AC Magnetic Measurements on Superconductors

2013 ◽  
pp. 208-222
Author(s):  
Philippe Laurent ◽  
Jean-François Fagnard ◽  
Philippe Vanderbemden
Keyword(s):  
Magnetic Properties ◽  
Temperature Distribution ◽  
Magnetic Measurements ◽  
Sampling Rate ◽  
Data Acquisition System ◽  
Magnetic Data ◽  
Magnetic Characterization ◽  
Set Up ◽  
Cryogenic Conditions

This work describes the design and realisation of an apparatus to measure simultaneously the AC magnetic properties and the temperature distribution on the top surface of bulk superconducting samples (up to 32 mm in diameter) in cryogenic conditions (temperature range 78-120 K). First the authors describe the experimental set-up used for simultaneous thermal and magnetic characterization of the sample. Next, the authors describe the practical considerations required for generating the large AC magnetic fields, possibly in the presence of DC fields. Then the authors present the data acquisition system allowing both temperature and magnetic data to be recorded at high a sampling rate.” The performances and limitations of the system are discussed.

scholarly journals Numerical modeling of the tide in the coast ar-ea Casablanca-Mohammedia (Morocco)

2017 ◽  
Vol 5 (1) ◽  
pp. 31
Author(s):  
Laila Mouakkir ◽  
Soumia Mordane
Keyword(s):  
Numerical Modeling ◽  
Coastal Area ◽  
Earth Rotation ◽  
Numerical Experiments ◽  
Bottom Topography ◽  
Dynamical Equations ◽  
Motion Equations ◽  
Tidal Circulation ◽  
The Earth ◽  
First Results

The objective of this study is to simulate the tidal circulation in the coastal area Casablanca-Mohammedia located on the Moroccan Atlantic. Simulations of the tidal currents of this zone use the 2D version of the MECCA (Model for Estuarine and Coastal Circulation Assessment). These simulations are based on the depth-integrated dynamical equations of turbulent motion. Equations are solved by using the implicit finite-differences techniques. The modelincorporates the actual bottom topography and the effects of the Earth rotation. As forcing mechanism, the model uses the tidal heights prescribed along the open boundaries.As first results, numerical experiments show that the model provides good results compared to those of the altymetric model TPXO.

Sign in / Sign up

Export Citation Format

Share Document