The double probe electric field experiment on Freja: Experiment description and first results

1994 ◽  
Vol 70 (3-4) ◽  
pp. 483-508 ◽  
Author(s):  
G. T. Marklund ◽  
L. G. Blomberg ◽  
P. -A. Lindqvist ◽  
C. -G. F�lthammar ◽  
G. Haerendel ◽  
...  
1994 ◽  
pp. 79-104 ◽  
Author(s):  
G. T. Marklund ◽  
L. G. Blomberg ◽  
P.-A. Lindqvist ◽  
C.-G. Fälthammar ◽  
G. Haerendel ◽  
...  

1996 ◽  
Vol 43 (6) ◽  
pp. 2767-2771 ◽  
Author(s):  
B. Johlander ◽  
R. Harboe-Sorensen ◽  
G. Olsson ◽  
L. Bylander

2021 ◽  
Author(s):  
Mats André ◽  
Anders I. Eriksson ◽  
Yuri V. Khotyaintsev ◽  
Sergio Toledo-Redondo

<p>Wakes behind scientific spacecraft caused by supersonic drifting ions is common in collisionless plasmas. Such wakes change the local plasma conditions and disturb in situ observations of the geophysical plasma parameters. We concentrate on observations of the electric field with double-probe instruments. Sometimes the wake effects are caused by the spacecraft body, are minor and easy to detect, and can be compensated for in a reasonable way. We show an example from the Cluster spacecraft in the solar wind. Sometimes the effects are caused by an electrostatic structure around a positively charged spacecraft causing an enhanced wake and major effects on the local plasma. Here observations of the geophysical electric field with the double-probe technique becomes impossible. Rather, the wake can be used to detect the presence of cold positive ions. Together with other instruments, also the cold ion flux can be estimated. We discuss such examples from the Cluster spacecraft in the magnetospheric lobes. For an intermediate range of parameters, when the drift energy of the ions is comparable to the equivalent charge of the spacecraft, also the charged wire booms of a double-probe instrument must be taken into account to extract useful information from the observations. We show an example from the MMS spacecraft near the magnetopause. With understanding of the physics causing wakes behind spacecraft, the local effects can sometimes be compensated for. When this is not possible, sometimes entirely new geophysical parameters can be estimated. An example is the flux of cold positive ions, constituting a major part of the mass outflow from planet Earth, using electric and magnetic field instruments on a spacecraft charged due to photoionization</p><p> </p>


2016 ◽  
Vol 3 (3) ◽  
pp. 1199-1207 ◽  
Author(s):  
Alexandre Lavrov ◽  
◽  
Kamila Gawel ◽  
Malin Torsæter

2020 ◽  
Author(s):  
Susana Barbosa ◽  
Mauricio Camilo ◽  
Carlos Almeida ◽  
José Almeida ◽  
Guilherme Amaral ◽  
...  

<p><span>The study of the electrical properties of the atmospheric marine boundary layer is important as the effect of natural radioactivity in driving near surface ionisation is significantly reduced over the ocean, and the concentration of aerosols is also typically lower than over continental areas, allowing a clearer examination of space-atmosphere interactions. Furthermore, cloud cover over the ocean is dominated by low-level clouds and most of the atmospheric charge lies near the earth surface, at low altitude cloud tops. </span></p><p><span>The relevance of electric field observations in the marine boundary layer is enhanced by the the fact that the electrical conductivity of the ocean air is clearly linked to global atmospheric pollution and aerosol content. The increase in aerosol pollution since the original observations made in the early 20th century by the survey ship Carnegie is a pressing and timely motivation for modern measurements of the atmospheric electric field in the marine boundary layer. Project SAIL (Space-Atmosphere-Ocean Interactions in the marine boundary Layer) addresses this challenge by means of an unique monitoring campaign on board the ship-rigged sailing ship NRP Sagres during its 2020 circumnavigation expedition. </span></p><p><span>The Portuguese Navy ship NRP Sagres departed from Lisbon on January 5th in a journey around the globe that will take 371 days. Two identical field mill sensors (CS110, Campbell Scientific) are installed </span><span>o</span><span>n the mizzen mast, one at a height of 22 m, and the other at a height of 5 meters. </span><span>A visibility sensor (SWS050, Biral) was also set-up on the same mast in order to have measurements of the extinction coefficient of the atmosphere and assess fair-weather conditions.</span><span> Further observations include gamma radiation measured with a NaI(Tl) scintillator from 475 keV to 3 MeV, cosmic radiation up to 17 MeV, and atmospheric ionisation from a cluster ion counter (Airel). The</span><span> 1 Hz measurements of the atmospheric electric field</span><span> and from all the other sensors</span><span> are </span><span>linked to the same rigorous temporal reference frame and precise positioning through kinematic GNSS observations. </span></p><p><span>Here the first results of the SAIL project will be presented, focusing on fair-weather electric field over the Atlantic. The observations obtained in the first three sections of the circumnavigation journey, including Lisbon (Portugal) - Tenerife (Spain), from 5 to 10 January, Tenerife - Praia (Cape Verde) from 13 to 19 January, and across the Atlantic from Cape Verde to Rio de Janeiro (Brasil), from January 22nd to February 14th, will be presented and discussed.</span></p>


2016 ◽  
pp. 137-165 ◽  
Author(s):  
P.-A. Lindqvist ◽  
G. Olsson ◽  
R. B. Torbert ◽  
B. King ◽  
M. Granoff ◽  
...  

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