Evaluation of strategies to manage remanent magnetization effects in magnetic field inversion

2006 ◽  
Author(s):  
Clive Foss
Keyword(s):  
Magnetic Field ◽  
Remanent Magnetization ◽  
Field Inversion

Magnetic field inversion and vortex chains in anisotropic superconductors

1990 ◽  
Vol 165-166 ◽  
pp. 1103-1104 ◽  
Author(s):  
A.M. Grishin ◽  
A.Yu. Martynovich ◽  
S.V. Yampolskii
Keyword(s):  
Magnetic Field ◽  
Anisotropic Superconductors ◽  
Field Inversion

scholarly journals Calibration of QM-MOURA three-axis magnetometer and gradiometer

2015 ◽  
Vol 4 (1) ◽  
pp. 1-18 ◽  
Author(s):  
M. Díaz-Michelena ◽  
R. Sanz ◽  
M. F. Cerdán ◽  
A. B. Fernández
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Geomagnetic Storm ◽  
Remanent Magnetization ◽  
Local Magnetic Field ◽  
Daily Variations ◽  
Scientific Goal ◽  
Solar Events

Abstract. MOURA instrument is a three-axis magnetometer and gradiometer designed and developed for Mars MetNet Precursor mission. The initial scientific goal of the instrument is to measure the local magnetic field in the surroundings of the lander i.e. to characterize the magnetic environment generated by the remanent magnetization of the crust and the superimposed daily variations of the field produced either by the solar wind incidence or by the thermomagnetic variations. Therefore, the qualification model (QM) will be tested in representative scenarios like magnetic surveys on terrestrial analogues of Mars and monitoring solar events, with the aim to achieve some experience prior to the arrival to Mars. In this work, we present a practical first approach for calibration of the instrument in the laboratory; a finer correction after the comparison of MOURA data with those of a reference magnetometer located in San Pablo de los Montes (SPT) INTERMAGNET Observatory; and a comparative recording of a geomagnetic storm as a demonstration of the compliance of the instrument capabilities with the scientific objectives.

scholarly journals Preferred orientation of ferromagnetic phases in rock-forming minerals: insights from magnetic anisotropy of single crystals

2019 ◽  
Vol 56 (9) ◽  
pp. 994-1001 ◽  
Author(s):  
Ann M. Hirt ◽  
Andrea R. Biedermann
Keyword(s):  
Magnetic Field ◽  
Magnetic Anisotropy ◽  
Single Crystals ◽  
Remanent Magnetization ◽  
Igneous Rocks ◽  
Flow Structures ◽  
Silicate Minerals ◽  
Fine Grained ◽  
Crystallographic Axes ◽  
Paleomagnetic Direction

In the early days of paleomagnetism, David Strangway was interested in understanding why igneous rocks are faithful recorders of the Earth’s magnetic field. He recognized that ferromagnetic (s.l.) grains that could be discerned by optical microscopy were too large to carry a stable remanent magnetization, and speculated whether fine-grained, ferromagnetic (s.l.) inclusions or exsolutions in silicate minerals are responsible. When these inclusions or exsolutions are randomly oriented, or the silicate hosts are randomly oriented in a rock, they can be a good recorder of the field. If these minerals, however, show an alignment within the silicate host, and the host is preferentially aligned due to flow structures or deformation, then the paleomagnetic direction and paleointensity could be biased. We examine the magnetic anisotropy arising from the ferromagnetic (s.l.) phases in silicate-host minerals. Single crystals of phyllosilicate, clinopyroxene, and calcite show most consistent ferrimagnetic fabric with relation to the minerals’ crystallographic axes, whereas olivine and feldspar display only a weak relationship. No discernable relationship is found between the ferrimagnetic anisotropy and crystallographic axes for amphibole minerals. Our results have implications when single crystals are being used for either studies of field direction or paleointensity or in cases where silicate minerals have a preferential orientation. Phyllosilicate minerals and pyroxene should be screened for significant magnetic anisotropy.

Magnetic Field Inversion – the cost of freedom

2019 ◽  
Vol 2019 (1) ◽  
pp. 1-5
Author(s):  
B. Vital Leonardo ◽  
Foss Clive ◽  
C. Oliveira Vanderlei ◽  
C. F. Barbosa Valeria
Keyword(s):  
Magnetic Field ◽  
The Cost ◽  
Field Inversion

Effects of remanent magnetization on dynamic magnetomechanical and magnetic-sensing characteristics in bi-layer multiferroics

2019 ◽  
Vol 85 (2) ◽  
pp. 20601
Author(s):  
Jitao Zhang ◽  
Weiwei Zhu ◽  
Dongyu Chen ◽  
Kang Li ◽  
Qingfang Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Lead Zirconate Titanate ◽  
Remanent Magnetization ◽  
Iron Alloy ◽  
Bias Field ◽  
Field Application ◽  
Quality Factors ◽  
Magnetic Sensing ◽  
Field Detection ◽  
Sensing Characteristics

Influences of remanent magnetization on dynamic magnetomechanical mechanisms in a bi-layer asymmetric magnetoelectric (ME) laminate consisting of lead zirconate titanate and samarium iron alloy has been studied systematically, and the underlying hysteresis physics involved in dynamic magnetomechanical process as well as its magnetic-sensing characteristics was intensively characterized. To appreciate the distinct magnetostriction and ferromagnetism simultaneously in samarium iron alloy, key magnetomechanical parameters of dynamic piezomagnetic coefficient, Young's modulus and mechanical quality factors exhibit hysteresis behaviors under magnetic field application. Consequently, high sensitivity in proposed bi-payer laminate for field detection can be reached without the facilitation of additional bias field. Experimental results show that the ME output has an approximately linear correlation with the applied AC magnetic field, and the low-frequency and the detection limits at 1 kHz and 120 kHz can reach 2.3 × 10−6 T and 2.2 × 10−8 T, respectively. These unique features provide such an asymmetric ME composite great potentials for weak magnetic field detection without DC bias field.

Direct determination of the natural remanent magnetization effect in a hole drilled in layered ground from magnetic field and susceptibility logs

Geophysics ◽  
1992 ◽  
Vol 57 (7) ◽  
pp. 872-884 ◽  
Author(s):  
Guy Desvignes ◽  
Véronique Barthes ◽  
Alain Tabbagh
Keyword(s):  
Magnetic Field ◽  
Remanent Magnetization ◽  
Direct Determination ◽  
Theoretical Models ◽  
Natural Remanent Magnetization ◽  
Case Examples ◽  
Joint Interpretation ◽  
The Fourier Transform ◽  
Layered Ground

A new method as presented, allows the joint interpretation of both electromagnetic (EM) and magnetic logs in layered ground, based on the fact that the susceptibility responses for these two measurements are linear. Thus we can make use of the classical properties of the Fourier transform to extract from these two signals the magnetic field due to remanent magnetization. Theoretical models show that for a sufficient sample step this remanent magnetization can be recovered, even if the Koenigsberger ratio is of the order of 0.2 and if the thickness of the magnetized layer is of the order of 1 m. The results for two case examples in a sedimentary context are also shown. Despite the difficulties due to experimental procedures, we show that the amplitude of the extracted information is significant in these two cases, even if its variations are somewhat structureless and cannot be easily explained by the geology.

Paleomagnetism of the Keweenawan Chipman Lake and Seabrook Lake carbonatite complexes, Ontario

1992 ◽  
Vol 29 (6) ◽  
pp. 1215-1223 ◽  
Author(s):  
D. T. A. Symons
Keyword(s):  
Magnetic Field ◽  
Remanent Magnetization ◽  
Pole Position ◽  
Alteration Zone ◽  
Contact Aureole ◽  
Isothermal Remanent Magnetization ◽  
Abitibi Subprovince ◽  
Normal Polarity ◽  
Reversed Polarity ◽  
Host Rocks

The Chipman Lake complex crops out as a series of carbonatite and related alkalic mafic dikes in the Wabigoon Subprovince of the Superior Province, whereas the Seabrook Lake complex crops out as an alkalic syenite – carbonatite stock in the Abitibi Subprovince. Paleomagnetic analysis was done on specimens from 23 and 19 sites located in and around the Chipman Lake and Seabrook Lake complexes, respectively, using detailed alternating-field and thermal step demagnetization and isothermal remanent magnetization tests. Contact tests with adjacent Archean host rocks show that both complexes retain a primary characteristic remanence (ChRM). The Chipman Lake's ChRM is retained in 11 dikes with normal polarity and one dike with reversed polarity and at one site with normal polarity and one site with reversed polarity from the fenite alteration zone. Its ChRM gives a pole position at 186°E, 38°N (dp = 7°, dm = 11°), which corresponds to a Keweenawan age of 1098 ± 10 Ma, suggesting that younger K–Ar amphibole ages do not date emplacement. The ChRM of the host rock, the Chipman Lake diorite stock, gives a pole at 49°E, 51°N (dp = 8°, dm = 13°), showing that it is not part of the Keweenawan complex but may be a 2.45 Ga Matachewan intrusive. The Seabrook Lake complex's ChRM is found at six normal polarity sites from within the complex and at four normal and three reversed polarity sites from within the fenitized Archean granite and Matachewan diabase of the contact aureole. It gives a pole position at 180°E, 46°N (dp = 11°, dm = 17°), which corresponds to a Keweenawan age of 1103 ± 10 Ma, agreeing with K/Ar biotite ages. The paleomagnetic data indicate that no significant motion on the Kapuskasing Structural Zone occurred after emplacement of the complexes excluding minor vertical uplift of less than about 4 km, and that there were multiple polarity transitions of a symmetric Earth's magnetic field during Keweenawan time.

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