Induction Arrows

2007 ◽  
pp. 412-413 ◽  
Author(s):  
Oliver Ritter
Keyword(s):  
Induction Arrows

scholarly journals Remote effects in real induction arrows

2009 ◽  
Vol 45 (5) ◽  
Author(s):  
A. Ádám
Keyword(s):  
Induction Arrows

The response of perturbation and induction arrows to a three‐dimensional buried anomaly

Geophysics ◽  
1982 ◽  
Vol 47 (1) ◽  
pp. 51-59 ◽  
Author(s):  
H. L. Lam ◽  
F. W. Jones ◽  
R. D. Hibbs
Keyword(s):  
Numerical Model ◽  
Three Dimensional ◽  
Great Depth ◽  
Spatial Extent ◽  
Conductivity Anomaly ◽  
Induction Arrow ◽  
The Earth ◽  
Induction Arrows ◽  
Quadrature Phase ◽  
Induced Currents

A numerical model is employed to calculate theoretical perturbation and induction arrows for a spatially confined three‐dimensional (3-D) conductivity anomaly located at various depths below the surface of the earth for two source periods. The results indicate that the magnitudes of the induction arrow decrease as the anomaly depth increases and the arrows point toward the conductive anomaly even at great depth below the surface. It is found that the extent of the anomalous induced currents depends upon the depth of the inhomogeneity and on the source field period. The ([Formula: see text]) perturbation arrow can be used to outline the spatial extent of the anomaly, and the ([Formula: see text]) quadrature‐phase arrows better indicate the spatial extent than the in‐phase arrows if the source period is not an optimum one.

scholarly journals The geomagnetic coast effect at two 80° S stations in Antarctica, observed in the ULF range

2018 ◽  
Vol 36 (1) ◽  
pp. 193-203 ◽  
Author(s):  
Mauro Regi ◽  
Marcello De Lauretis ◽  
Patrizia Francia ◽  
Stefania Lepidi ◽  
Andrea Piancatelli ◽  
...  
Keyword(s):  
Spectral Power ◽  
Azimuthal Angle ◽  
Vertical Component ◽  
Field Measurements ◽  
Correction Method ◽  
Reference Station ◽  
Coast Effect ◽  
Single Station ◽  
Induction Arrows ◽  
Storms And Substorms

Abstract. We examined the coast effect in Antarctica along the 80∘ S magnetic parallel. We used the geomagnetic field measurements at the two coastal stations of Mario Zucchelli Station and Scott Base, and, as a reference, at the inland temporary station Talos Dome, during 18 January–14 March 2008. Spectral analysis in the Pc5 frequency range (1–7 mHz) revealed large differences between coastal and inland stations, such as higher spectral power levels in the vertical component and higher coherence between horizontal and vertical components at coastal stations. Using the interstation method on selected active time intervals, with Talos Dome as a remote reference station, we found that remote reference induction arrows are directed almost perpendicularly with respect to their respective coastlines. Moreover, the single-station analysis shows that at Talos Dome the amplitude of the induction arrows is much smaller than at coastal stations. These results clearly indicate that coast effect at a few hundred kilometers from the coastline is relatively small. The coast effect on polarization parameters was examined, for a Pc5 event that occurred on 11 March 2008. The results evidenced that the azimuthal angle of polarized signals at one of the coastal stations is largely different with respect to the inland station (by ∼ 110∘), while the polarization ratio and ellipticity attain comparable values. We proposed a correction method of the polarization parameters, which operates directly in the frequency domain, obtaining comparable azimuthal angles at coastal and inland stations. Keywords. Ionosphere (wave propagation) – magnetospheric physics (polar cap phenomena; storms and substorms)

scholarly journals Induction arrows from offshore floating magnetometers using land reference data

2000 ◽  
Vol 140 (2) ◽  
pp. 442-452 ◽  
Author(s):  
A. P. Hitchman ◽  
F. E. M. Lilley ◽  
P. R. Milligan
Keyword(s):  
Reference Data ◽  
Induction Arrows

Induction arrows for a buried conducting plate

1983 ◽  
Vol 32 (4) ◽  
pp. 306-311 ◽  
Author(s):  
W. Nienaber ◽  
David Hebert ◽  
H.W. Dosso
Keyword(s):  
Conducting Plate ◽  
Induction Arrows

scholarly journals On the relevance of source effects in geomagnetic pulsations for induction soundings

2018 ◽  
Vol 36 (2) ◽  
pp. 337-347 ◽  
Author(s):  
Anne Neska ◽  
Jan Tadeusz Reda ◽  
Mariusz Leszek Neska ◽  
Yuri Petrovich Sumaruk
Keyword(s):  
Field Line ◽  
Electromagnetic Induction ◽  
Transfer Functions ◽  
Equatorial Region ◽  
Impedance Tensor ◽  
Geomagnetic Pulsations ◽  
Correlated Noise ◽  
Field Line Resonances ◽  
Induction Arrows ◽  
Depth Sounding

Abstract. This study is an attempt to close a gap between recent research on geomagnetic pulsations and their usage as source signals in electromagnetic induction soundings (i.e., magnetotellurics, geomagnetic depth sounding, and magnetovariational sounding). The plane-wave assumption as a precondition for the proper performance of these methods is partly violated by the local nature of field line resonances which cause a considerable portion of pulsations at mid latitudes. It is demonstrated that and explained why in spite of this, the application of remote reference stations in quasi-global distances for the suppression of local correlated-noise effects in induction arrows is possible in the geomagnetic pulsation range. The important role of upstream waves and of the magnetic equatorial region for such applications is emphasized. Furthermore, the principal difference between application of reference stations for local transfer functions (which result in sounding curves and induction arrows) and for inter-station transfer functions is considered. The preconditions for the latter are much stricter than for the former. Hence a failure to estimate an inter-station transfer function to be interpreted in terms of electromagnetic induction, e.g., because of field line resonances, does not necessarily prohibit use of the station pair for a remote reference estimation of the impedance tensor.

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