scholarly journals A review of the quantitative links between CMEs and magnetic clouds

2008 ◽  
Vol 26 (10) ◽  
pp. 3113-3125 ◽  
Author(s):  
P. Démoulin
Keyword(s):  
Magnetic Field ◽  
Field Measurements ◽  
Magnetic Clouds ◽  
Special Focus ◽  
Interplanetary Coronal Mass Ejections ◽  
Magnetic Field Data ◽  
One Dimensional ◽  
Expected Time ◽  
Measured Magnetic Field

Abstract. Magnetic clouds (MCs), and more generally, interplanetary coronal mass ejections (ICMEs), are believed to be the interplanetary counterparts of CMEs. The link has usually been shown by taking into account the CME launch position on the Sun, the expected time delay and by comparing the orientation of the coronal and interplanetary magnetic field. Making such a link more quantitative is challenging since it requires a relation between very different kinds of magnetic field measurements: (i) photospheric magnetic maps, which are observed from a distant vantage point (remote sensing) and (ii) in-situ measurements of MCs, which provide precise, directly measured, magnetic field data merely from one-dimensional linear samples. The association between events in these different domains can be made using adequate coronal and MC models. Then, global quantities like magnetic fluxes and helicity can be derived and compared. This review paper describes all the general trends found in the above association criteria. A special focus is given for the cases which do not follow the earlier derived mean laws since interesting physics is usually involved.

scholarly journals Principal Component Gradiometer technique for removal of spacecraft-generated disturbances from magnetic field data

2020 ◽  
Author(s):  
Ovidiu Dragoş Constantinescu ◽  
Hans-Ulrich Auster ◽  
Magda Delva ◽  
Olaf Hillenmaier ◽  
Werner Magnes ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Principal Component ◽  
Field Measurements ◽  
Magnetic Field Data ◽  
Service Oriented ◽  
Sensor Configuration ◽  
Time Required ◽  
First Time ◽  
The Magnetic Field

Abstract. In situ measurement of the magnetic field using space borne instruments requires either a magnetically clean platform and/or a very long boom for accommodating magnetometer sensors at a large distance from the spacecraft body. This significantly drives up the costs and time required to build a spacecraft. Here we present an alternative sensor configuration and an algorithm allowing for ulterior removal of the spacecraft generated disturbances from the magnetic field measurements, thus lessening the need for a magnetic cleanliness program and allowing for shorter boom length. The proposed algorithm is applied to the Service Oriented Spacecraft Magnetometer (SOSMAG) onboard the Korean geostationary satellite GeoKompsat-2A (GK2A) which uses for the first time a multi-sensor configuration for onboard data cleaning. The successful elimination of disturbances originating from several sources validates the proposed cleaning technique.

Statistical relations between in-situ measured Bz component and thermospheric density variations

2021 ◽  
Author(s):  
Sofia Kroisz ◽  
Lukas Drescher ◽  
Manuela Temmer ◽  
Sandro Krauss ◽  
Barbara Süsser-Rechberger ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Field Measurements ◽  
Satellite Orbit ◽  
Solar Wind Plasma ◽  
Statistical Investigation ◽  
Neutral Density ◽  
Special Focus ◽  
Short Term

<p>Through advanced statistical investigation and evaluation of solar wind plasma and magnetic field data, we investigate the statistical relation between the magnetic field B<sub>z</sub> component, measured at L1, and Earth’s thermospheric neutral density. We will present preliminary results of the time series analyzes using in-situ plasma and magnetic field measurements from different spacecraft in near Earth space (e.g., ACE, Wind, DSCOVR) and relate those to derived thermospheric densities from various satellites (e.g., GRACE, CHAMP). The long and short term variations and dependencies in the solar wind data are related to variations in the neutral density of the thermosphere and geomagnetic indices. Special focus is put on the specific signatures that stem from coronal mass ejections and stream or corotating interaction regions.  The results are used to develop a novel short-term forecasting model called SODA (Satellite Orbit DecAy). This is a joint study between TU Graz and University of Graz funded by the FFG Austria (project “SWEETS”).</p>

scholarly journals Maximum-variance gradiometer technique for removal of spacecraft-generated disturbances from magnetic field data

2020 ◽  
Vol 9 (2) ◽  
pp. 451-469
Author(s):  
Ovidiu Dragoş Constantinescu ◽  
Hans-Ulrich Auster ◽  
Magda Delva ◽  
Olaf Hillenmaier ◽  
Werner Magnes ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Measurements ◽  
Magnetic Field Data ◽  
Maximum Variance ◽  
Service Oriented ◽  
Corrected Data ◽  
Sensor Configuration ◽  
Time Required ◽  
The Magnetic Field

Abstract. In situ measurement of the magnetic field using spaceborne instruments requires a magnetically clean platform and/or a very long boom for accommodating magnetometer sensors at a large distance from the spacecraft body. This significantly drives up the costs and the time required to build a spacecraft. Here we present an alternative sensor configuration and a technique allowing for removal of the spacecraft-generated AC disturbances from the magnetic field measurements, thus lessening the need for a magnetic cleanliness programme and allowing for shorter boom length. The final expression of the corrected data takes the form of a linear combination of the measurements from all sensors, allowing for simple onboard software implementation. The proposed technique is applied to the Service Oriented Spacecraft Magnetometer (SOSMAG) on board the Korean geostationary satellite GeoKompsat-2A (GK2A). In contrast to other missions where multi-sensor measurements were used to clean the data on the ground, the SOSMAG instrument performs the cleaning on board and transmits the corrected data in real time, as needed by space weather applications. The successful elimination of the AC disturbances originating from several sources validates the proposed cleaning technique.

scholarly journals Contribution of the ageing effect to the observed asymmetry of interplanetary magnetic clouds

2020 ◽  
Vol 639 ◽  
pp. A6
Author(s):  
P. Démoulin ◽  
S. Dasso ◽  
V. Lanabere ◽  
M. Janvier
Keyword(s):  
Magnetic Field ◽  
Magnetic Clouds ◽  
Magnetic Configuration ◽  
Ageing Effect ◽  
Interplanetary Coronal Mass Ejections ◽  
Spatial Coordinate ◽  
In Situ Data ◽  
Spacecraft Trajectory ◽  
Solar Eruptions

Context. Large magnetic structures are launched away from the Sun during solar eruptions. They are observed as (interplanetary) coronal mass ejections (ICMEs or CMEs) with coronal and heliospheric imagers. A fraction of them are observed in situ as magnetic clouds (MCs). Fitting these structures properly with a model requires a better understanding of their evolution. Aims. In situ measurements are made locally when the spacecraft trajectory crosses the magnetic configuration. These observations are taken for different elements of plasma and at different times, and are therefore biased by the expansion of the magnetic configuration. This ageing effect means that stronger magnetic fields are measured at the front than at the rear of MCs. This asymmetry is often present in MC data. However, the question is whether the observed asymmetry can be explained quantitatively from the expansion alone. Methods. Based on self-similar expansion, we derived a method for estimating the expansion rate from the observed plasma velocity. We next corrected the observed magnetic field and the spatial coordinate along the spacecraft trajectory for the ageing effect. This provided corrected data as in the case when the MC internal structure were observed at the same time. Results. We apply the method to 90 best-observed MCs near Earth (1995–2012). The ageing effect is the main source of the observed magnetic asymmetry for only 28% of the MCs. After correcting for the ageing effect, the asymmetry is almost symmetrically distributed between MCs with a stronger magnetic field at the front and those at the rear of MCs. Conclusions. The proposed method can efficiently remove the ageing bias within in situ data of MCs, and more generally, of ICMEs. This allows us to analyse the data with a spatial coordinate, such as in models or remote-sensing observations.

Overview of interplanetary coronal mass ejections observed by Solar Orbiter, Parker Solar Probe, Bepi Colombo, Wind and STEREO-A

2021 ◽  
Author(s):  
Christian Möstl ◽  
Andreas J. Weiss ◽  
Rachel L. Bailey ◽  
Martin A. Reiss ◽  
Tanja Amerstorfer ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Data ◽  
First Year ◽  
Interplanetary Coronal Mass Ejections ◽  
Rotating Magnetic Fields ◽  
Multiple Points ◽  
Magnetic Field Data ◽  
In Situ Observations ◽  
Heliospheric Imager

<p>We show in situ observations of ICMEs during the first year of Solar Orbiter observations based on magnetic field data from the MAG instrument in conjunction with in situ and imaging observations from the Heliospheric System Observatory. The in situ magnetic field data from four other currently active spacecraft - Parker Solar Probe, BepiColombo, STEREO-Ahead and Wind -  are also searched for ICME signatures, and all clear ICME events that could be identified by classic signatures such as elevated and rotating magnetic fields of sufficiently long durations are included in a living online catalog. Furthermore, we provide a visualization of the in situ magnetic field data alongside spacecraft positions and propagating CME fronts, which are based on modeling of STEREO-A heliospheric imager data. This allows us to identify ICME events that could be unambiguously followed from their inception on the Sun to their impact at the aforementioned spacecraft, and highlights sought-after lineup events, in which the same ICME is observed at multiple points in space, such as the well-studied 2020 April 15-20 ICME. We discuss the ICME rate observed so far, and provide an outlook on the expected ICME rate in solar cycle 25 based on different forecasts for the cycle amplitude (see Möstl et al. 2020, https://doi.org/10.3847/1538-4357/abb9a1).</p>

In Situ Synthesis of One-Dimensional Nanocrystalline Iron Materials by Electrodeposition Under Magnetic Field

2012 ◽  
Vol 42 (9) ◽  
pp. 1211-1216
Author(s):  
Qiaoxin Zhang ◽  
Shaofeng Zhou ◽  
Jiaming Zhang ◽  
Liang Zhang ◽  
Lining Yang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
In Situ Synthesis ◽  
One Dimensional ◽  
Nanocrystalline Iron

scholarly journals A high resolution lithospheric magnetic field model over southern Africa based on a joint inversion of CHAMP, Swarm, WDMAM and ground magnetic field data

2018 ◽  
Author(s):  
Foteini Vervelidou ◽  
Erwan Thébault ◽  
Monika Korte
Keyword(s):  
Magnetic Field ◽  
Southern Africa ◽  
Field Model ◽  
Joint Inversion ◽  
Field Measurements ◽  
Magnetic Field Data ◽  
Magnetic Field Model ◽  
Lithospheric Magnetic Field ◽  
The Mean ◽  
Ground Magnetic

Abstract. We derive a lithospheric magnetic field model up to equivalent Spherical Harmonic degree 1000 over southern Africa. We rely on a joint inversion of satellite, near-surface and ground magnetic field data. The input data set consists of magnetic field vector measurements from the CHAMP satellite, across-track magnetic field differences from the Swarm mission, the World Digital Magnetic Anomaly Map and magnetic field measurements from repeat stations and three local INTERMAGNET observatories. For the inversion scheme, we use the Revised-Spherical Cap Harmonic Analysis (R-SCHA), a regional analysis technique able to deal with magnetic field measurements obtained at different altitudes. The model is carefully assessed and displayed at different altitudes and its spectral content is compared to high resolution global lithospheric field models. By comparing the shape of its spectrum to a statistical power spectrum of Earth's lithospheric magnetic field, we infer the mean magnetic thickness and the mean magnetization over southern Africa.

Cleaning magnetometer data using multi sensor configuration

2020 ◽  
Author(s):  
Dragos Constantinescu ◽  
Hans-Ulrich Auster ◽  
Magda Delva ◽  
Olaf Hillenmaier ◽  
Werner Magnes ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Measurements ◽  
Sensor Arrangement ◽  
Magnetometer Data ◽  
Service Oriented ◽  
Sensor Configuration ◽  
First Time ◽  
The Magnetic Field ◽  
Magnetic Cleanliness

<p>Measuring the in situ magnetic field using space borne instruments requires either a magnetically clean platform and/or a very long boom for accommodating magnetometers sensors at a large distance from the spacecraft body. This significantly drives up the costs and time for building the spacecraft. Here we present an alternative sensor configuration and an algorithm allowing for ulterior removing of the spacecraft generated disturbances from the magnetic field measurements, thus lessening the need for a magnetic cleanliness program.</p><p>The Service Oriented Spacecraft Magnetometer (SOSMAG) onboard the Korean Geostationary Satellite GEO-KOMPSAT-2A (GK-2A) uses for the first time a multi-sensor configuration for onboard data cleaning. To remove the AC disturbances, a combination of the measurements from sensors placed at different positions from the disturbance sources is processed onboard. Sensor biases due to daily temperature variations are also removed using the specific SOSMAG sensor arrangement. </p><p> </p>

The PTB electromagnetic undulator for BESSY II

1998 ◽  
Vol 5 (3) ◽  
pp. 451-452 ◽  
Author(s):  
R. Klein ◽  
J. Bahrdt ◽  
D. Herzog ◽  
G. Ulm
Keyword(s):  
Magnetic Field ◽  
Field Data ◽  
Tuning Range ◽  
Period Length ◽  
Design Parameters ◽  
Magnetic Field Data ◽  
Electromagnetic Design ◽  
Special Mode ◽  
Main Design ◽  
Measured Magnetic Field

The Physikalisch-Technische Bundesanstalt (PTB) will operate an electromagnetic undulator designed for radiometry at the BESSY II storage ring. The undulator has a period length of 180 mm, 21 full periods and a maximum magnetic induction of 0.46 T, resulting in a tuning range of the first harmonic from 5 to 150 eV at 1.7 GeV electron energy. Moreover, the electromagnetic design allows the undulator to be operated in a special mode with the period length doubled to 360 mm, thus accordingly shifting the tuning range to lower energies. The main design parameters of the undulator for radiometric applications, as well as measured magnetic field data, are presented.

scholarly journals Configuration of a Magnetic Cloud From Solar Orbiter and Wind Spacecraft In-situ Measurements

2021 ◽  
Vol 9 ◽  
Author(s):  
Qiang Hu ◽  
Wen He ◽  
Lingling Zhao ◽  
Edward Lu
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Flux Rope ◽  
3D Models ◽  
Field Configuration ◽  
Magnetic Clouds ◽  
Physical Parameters ◽  
The Sun ◽  
Wind Spacecraft

Coronal mass ejections (CMEs) represent one type of the major eruption from the Sun. Their interplanetary counterparts, the interplanetary CMEs (ICMEs), are the direct manifestations of these structures when they propagate into the heliosphere and encounter one or more observing spacecraft. The ICMEs generally exhibit a set of distinctive signatures from the in-situ spacecraft measurements. A particular subset of ICMEs, the so-called Magnetic Clouds (MCs), is more uniquely defined and has been studied for decades, based on in-situ magnetic field and plasma measurements. By utilizing the latest multiple spacecraft measurements and analysis tools, we report a detailed study of the internal magnetic field configuration of an MC event observed by both the Solar Orbiter (SO) and Wind spacecraft in the solar wind near the Sun-Earth line. Both two-dimensional (2D) and three-dimensional (3D) models are applied to reveal the flux rope configurations of the MC. Various geometrical as well as physical parameters are derived and found to be similar within error estimates for the two methods. These results quantitatively characterize the coherent MC flux rope structure crossed by the two spacecraft along different paths. The implication for the radial evolution of this MC event is also discussed.

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