In Which Magnetotail Hemisphere is a Satellite? Problems Using in Situ Magnetic Field Data

Abstract. Previous observations have provided a clear indication that the dusk-dawn (v⊥y) sense of both slow (< 200 km s−1) and fast (> 200 km s−1) convective magnetotail flows is strongly governed by the Interplanetary Magnetic Field (IMF) By conditions. The related “untwisting hypothesis” of magnetotail dynamics is commonly invoked to explain this dependence, in terms of a large-scale magnetospheric asymmetry. In the current study, we present Cluster spacecraft observations from 12 October 2006 of earthward convective magnetotail plasma flows whose dusk-dawn sense disagrees with the untwisting hypothesis of IMF By control of the magnetotail flows. During this interval, observations of the upstream solar wind conditions from OMNI, and ionospheric convection data using SuperDARN, indicate a large-scale magnetospheric morphology consistent with positive IMF By penetration into the magnetotail. Inspection of the in-situ Cluster magnetic field data reveals a flapping of the magnetotail current sheet; a phenomenon known to influence dusk-dawn flow. Results from the curlometer analysis technique suggest that the dusk-dawn flow perturbations may have been driven by the J x B force associated with a dawnward-propagating flapping of the magnetotail current sheet, locally overriding the expected IMF By control of the flows. We conclude that invocation of the untwisting hypothesis may be inappropriate when interpreting intervals of dynamic magnetotail behaviour such as during current sheet flapping.

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Interplanetary shocks at 5 AU and their effects on Jupiter's decametric radio emissions

10.5194/egusphere-egu2020-2395 ◽

2020 ◽

Author(s):

Ezequiel Echer

Keyword(s):

Magnetic Field ◽

Field Data ◽

Heliocentric Distance ◽

Solar Wind Plasma ◽

Interplanetary Shock ◽

Interplanetary Shocks ◽

Magnetic Field Data ◽

Radio Emissions ◽

Abrupt Changes

<p>Interplanetary shocks cause large and abrupt changes in solar wind plasma and magnetic field parameters. Shock occurrence and strength are dependent on the heliocentric distance. Further, shocks have important effects on planetary magnetospheres, such as causing large magnetospheric compressions or expansions, and triggering auroral activity emissions. In this work recent results regarding interplanetary shock parameters determined from analysis of in-situ spacecraft plasma and magnetic field data measured near Jupiter&#8217;s orbit are presented. The distribution of parameters for both fast forward and fast reverse shocks is analysed and compared with interplanetary shocks detected at other heliocentric distances, Further, an analysis of &#160;interplanetary shock effects on Jupiter decametric auroral radio emissions independent of Io (non-Io DAM) is presented.&#160;</p>

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

10.5194/egusphere-egu21-592 ◽

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 - &#160;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.&#160;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 M&#246;stl et al. 2020, https://doi.org/10.3847/1538-4357/abb9a1).</p>

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An Augmented Iteratively Re-weighted and Refined Least Squares Method for lp Minimization Problem in Inverse Modeling of Potential Field Magnetic Data

Journal of Geological Research ◽

10.30564/jgr.v1i3.1316 ◽

2020 ◽

Vol 1 (3) ◽

Author(s):

Maysam Abedi

Keyword(s):

Magnetic Field ◽

Magnetic Susceptibility ◽

Least Squares ◽

Minimization Problem ◽

Potential Field ◽

Field Data ◽

Least Squares Method ◽

Porphyry Copper ◽

Magnetic Data ◽

Magnetic Field Data

The presented work examines application of an Augmented Iteratively Re-weighted and Refined Least Squares method (AIRRLS) to construct a 3D magnetic susceptibility property from potential field magnetic anomalies. This algorithm replaces an lp minimization problem by a sequence of weighted linear systems in which the retrieved magnetic susceptibility model is successively converged to an optimum solution, while the regularization parameter is the stopping iteration numbers. To avoid the natural tendency of causative magnetic sources to concentrate at shallow depth, a prior depth weighting function is incorporated in the original formulation of the objective function. The speed of lp minimization problem is increased by inserting a pre-conditioner conjugate gradient method (PCCG) to solve the central system of equation in cases of large scale magnetic field data. It is assumed that there is no remanent magnetization since this study focuses on inversion of a geological structure with low magnetic susceptibility property. The method is applied on a multi-source noise-corrupted synthetic magnetic field data to demonstrate its suitability for 3D inversion, and then is applied to a real data pertaining to a geologically plausible porphyry copper unit. The real case study located in Semnan province of Iran consists of an arc-shaped porphyry andesite covered by sedimentary units which may have potential of mineral occurrences, especially porphyry copper. It is demonstrated that such structure extends down at depth, and consequently exploratory drilling is highly recommended for acquiring more pieces of information about its potential for ore-bearing mineralization.

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A reexamination of “interstellar ion waves” previously identified in Pioneer 10 magnetic field data

Geophysical Research Letters ◽

10.1029/98gl02802 ◽

1998 ◽

Vol 25 (19) ◽

pp. 3721-3724 ◽

Cited By ~ 3

Author(s):

Neil Murphy ◽

Edward J. Smith ◽

Joyce Wolf ◽

Devrie S. Intriligator

Keyword(s):

Magnetic Field ◽

Field Data ◽

Magnetic Field Data ◽

Ion Waves ◽

Pioneer 10

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Ogo 5 magnetic-field data near the Earth's bow shock: A correlation with theory

Journal of Geophysical Research Atmospheres ◽

10.1029/ja077i004p00604 ◽

1972 ◽

Vol 77 (4) ◽

pp. 604-610 ◽

Cited By ~ 19

Author(s):

J. K. Guha ◽

D. L. Judge ◽

J. H. Marburger

Keyword(s):

Magnetic Field ◽

Field Data ◽

Bow Shock ◽

Magnetic Field Data ◽

Earth’S Bow Shock

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Using an induction coil sensor to indirectly measure the B-field response in the bandwidth of the transient electromagnetic method

Geophysics ◽

10.1190/1.1444837 ◽

2000 ◽

Vol 65 (5) ◽

pp. 1489-1494 ◽

Cited By ~ 34

Author(s):

Richard S. Smith ◽

A. Peter Annan

Keyword(s):

Magnetic Field ◽

Field Data ◽

Indirect Measurement ◽

Rate Of Change ◽

Induction Coil ◽

Voltage Response ◽

Magnetic Field Data ◽

Transient Electromagnetic ◽

Different Characteristics ◽

The Magnetic Field

The traditional sensor used in transient electromagnetic (EM) systems is an induction coil. This sensor measures a voltage response proportional to the time rate of change of the magnetic field in the EM bandwidth. By simply integrating the digitized output voltage from the induction coil, it is possible to obtain an indirect measurement of the magnetic field in the same bandwidth. The simple integration methodology is validated by showing that there is good agreement between synthetic voltage data integrated to a magnetic field and synthetic magnetic‐field data calculated directly. Further experimental work compares induction‐coil magnetic‐field data collected along a profile with data measured using a SQUID magnetometer. These two electromagnetic profiles look similar, and a comparison of the decay curves at a critical point on the profile shows that the two types of measurements agree within the bounds of experimental error. Comparison of measured voltage and magnetic‐field data show that the two sets of profiles have quite different characteristics. The magnetic‐field data is better for identifying, discriminating, and interpreting good conductors, while suppressing the less conductive targets. An induction coil is therefore a suitable sensor for the indirect collection of EM magnetic‐field data.

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Analytical Signal and Reduction to Pole Interpretation of Total Magnetic Field Data at Eppawala Phosphate Deposit

Journal of Geoscience and Environment Protection ◽

10.4236/gep.2014.23023 ◽

2014 ◽

Vol 02 (03) ◽

pp. 181-189

Author(s):

N. D. Subasinghe ◽

W. K. D. G. D. R. Charles ◽

S. N. De Silva

Keyword(s):

Magnetic Field ◽

Field Data ◽

Analytical Signal ◽

Magnetic Field Data ◽

Total Magnetic Field ◽

Phosphate Deposit

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

10.5194/gi-2020-10 ◽

2020 ◽

Cited By ~ 1

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.

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