scholarly journals The longitudinal polar cusp displacement from geomagnetic measurements in Antarctica

2019 ◽  
Vol 61 (Vol 61 (2018)) ◽  
Author(s):  
Martina Marzocchetti ◽  
Stefania Lepidi ◽  
Patrizia Francia ◽  
Lili Cafarella ◽  
Domenico Di Mauro
Keyword(s):  
Polar Cusp ◽  
Geomagnetic Measurements

1-pT Noise Fluxgate Magnetometer for Geomagnetic Measurements and Unshielded Magnetocardiography

2020 ◽  
Vol 69 (5) ◽  
pp. 2552-2560
Author(s):  
Michal Janosek ◽  
Mattia Butta ◽  
Michal Dressler ◽  
Elda Saunderson ◽  
David Novotny ◽  
...  
Keyword(s):  
Fluxgate Magnetometer ◽  
Geomagnetic Measurements

scholarly journals On the crustal bias of repeat stations in Romania

2013 ◽  
Vol 55 (6) ◽  
Author(s):  
Venera Dobrica ◽  
Crisan Demetrescu ◽  
Razvan Greculeasa ◽  
Anca Isac
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Curie Temperature ◽  
Magnetic Induction ◽  
Electromagnetic Induction ◽  
Reference Station ◽  
Lateral Variation ◽  
Field Campaigns ◽  
Induction Model ◽  
Geomagnetic Measurements

<p>A magnetic induction model has been applied to recordings obtained in 2010 during the field campaigns for geomagnetic measurements at the 26 repeat stations of the Romanian secular variation network. The model is based on the observation that a variable external magnetic field induces a response of the Earth's interior not only by electromagnetic induction, but also by magnetic induction in the magnetic rocks above the Curie temperature. The model computes coefficients of a linear relationship between recorded values of a certain geomagnetic element (X, Y, Z, or F) at the repeat station and recorded X, Y, Z values at a reference station (in this case, SUA observatory). Coefficients depend on magnetic permeabilities of rocks beneath the station and stand as a proxy for the anomaly bias characterizing the site. Maps of the lateral variation of this type of information were obtained and discussed.</p>

scholarly journals A multi-satellite study of accelerated ionospheric ion beams above the polar cap

2006 ◽  
Vol 24 (6) ◽  
pp. 1665-1684 ◽  
Author(s):  
R. Maggiolo ◽  
J. A. Sauvaud ◽  
D. Fontaine ◽  
A. Teste ◽  
E. Grigorenko ◽  
...  
Keyword(s):  
Electric Field ◽  
Potential Drop ◽  
Auroral Zone ◽  
Ion Beams ◽  
Distribution Functions ◽  
Convection Velocity ◽  
Polar Cap ◽  
Ion Energy ◽  
Polar Cusp ◽  
Oxygen Ions

Abstract. This paper presents a study of nearly field-aligned outflowing ion beams observed on the Cluster satellites over the polar cap. Data are taken at geocentric radial distances of the order of 5–9 RE. The distinction is made between ion beams originating from the polar cusp/cleft and beams accelerated almost along the magnetic field line passing by the spacecraft. Polar cusp beams are characterized by nearly field-aligned proton and oxygen ions with an energy ratio EO+ / EH+, of the order of 3 to 4, due to the ion energy repartition inside the source and to the latitudinal extension of the source. Rapid variations in the outflowing ion energy are linked with pulses/modifications of the convection electric field. Cluster data allow one to show that these perturbations of the convection velocity and the associated ion structures propagate at the convection velocity. In contrast, polar cap local ion beams are characterized by field-aligned proton and oxygen ions with similar energies. These beams show the typical inverted V structures usually observed in the auroral zone and are associated with a quasi-static converging electric field indicative of a field-aligned electric field. The field-aligned potential drop fits well the ion energy profile. The simultaneous observation of precipitating electrons and upflowing ions of similar energies at the Cluster orbit indicates that the spacecraft are crossing the mid-altitude part of the acceleration region. In the polar cap, the parallel electric field can thus extend to altitudes higher than 5 Earth radii. A detailed analysis of the distribution functions shows that the ions are heated during their parallel acceleration and that energy is exchanged between H+ and O+. Furthermore, intense electrostatic waves are observed simultaneously. These observations could be due to an ion-ion two-stream instability.

Electrodynamics of the polar cusp ionosphere; A case study

1989 ◽  
Vol 94 (A6) ◽  
pp. 6713-6722 ◽  
Author(s):  
P. E. Sandholt ◽  
B. Jacobsen ◽  
B. Lybekk ◽  
A. Egeland ◽  
P. F. Bythrow ◽  
...  
Keyword(s):  
Polar Cusp

Staircase ion signature in the polar cusp: A case study

1992 ◽  
Vol 19 (17) ◽  
pp. 1735-1738 ◽  
Author(s):  
C. P. Escoubet ◽  
M. F. Smith ◽  
S. F. Fung ◽  
P. C. Anderson ◽  
R. A. Hoffman ◽  
...  
Keyword(s):  
Polar Cusp

Polar Cusp Features Observed By DMSP Satellites

1985 ◽  
pp. 177-192 ◽  
Author(s):  
C.-I. Meng ◽  
M. Candidi
Keyword(s):  
Polar Cusp
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