scholarly journals Extremely Low-Frequency Waves Inside the Diamagnetic Cavity of Comet 67P/Churyumov-Gerasimenko

2018 ◽  
Vol 45 (9) ◽  
pp. 3854-3864 ◽  
Author(s):  
B. Madsen ◽  
C. Simon Wedlund ◽  
A. Eriksson ◽  
C. Goetz ◽  
T. Karlsson ◽  
...  
Keyword(s):  
Low Frequency ◽  
Extremely Low Frequency ◽  
Comet 67P ◽  
Low Frequency Waves

scholarly journals Two-point observations of low-frequency waves at 67P/Churyumov-Gerasimenko during the descent of PHILAE: comparison of RPCMAG and ROMAP

2016 ◽  
Vol 34 (7) ◽  
pp. 609-622 ◽  
Author(s):  
Ingo Richter ◽  
Hans-Ulrich Auster ◽  
Gerhard Berghofer ◽  
Chris Carr ◽  
Emanuele Cupido ◽  
...  
Keyword(s):  
Low Frequency ◽  
Minimum Variance ◽  
Wave Source ◽  
Frequency Wave ◽  
Final Destination ◽  
Connection Line ◽  
New Type ◽  
Current Instability ◽  
Comet 67P ◽  
Low Frequency Waves

Abstract. The European Space Agency's spacecraft ROSETTA has reached its final destination, comet 67P/Churyumov-Gerasimenko. Whilst orbiting in the close vicinity of the nucleus the ROSETTA magnetometers detected a new type of low-frequency wave possibly generated by a cross-field current instability due to freshly ionized cometary water group particles. During separation, descent and landing of the lander PHILAE on comet 67P/Churyumov-Gerasimenko, we used the unique opportunity to perform combined measurements with the magnetometers onboard ROSETTA (RPCMAG) and its lander PHILAE (ROMAP). New details about the spatial distribution of wave properties along the connection line of the ROSETTA orbiter and the lander PHILAE are revealed. An estimation of the observed amplitude, phase and wavelength distribution will be presented as well as the measured dispersion relation, characterizing the new type of low-frequency waves. The propagation direction and polarization features will be discussed using the results of a minimum variance analysis. Thoughts about the size of the wave source will complete our study.

scholarly journals Progress in the Knowledge, Application and Influence of Extremely Low Frequency Signals

2020 ◽  
Vol 10 (10) ◽  
pp. 3494
Author(s):  
Rosa M. García ◽  
Nuria Novas ◽  
Alfredo Alcayde ◽  
Dalia El Khaled ◽  
Manuel Fernández-Ros ◽  
...  
Keyword(s):  
Low Frequency ◽  
Collaborative Relationships ◽  
Temporal Perspective ◽  
Knowledge Application ◽  
Extremely Low Frequency ◽  
Essential Step ◽  
Extra Effort ◽  
The Usa ◽  
Low Frequency Waves ◽  
Selection Of

This paper describes the characteristics of contributions made by researchers worldwide in the field of ELF (extremely low frequency) waves from 1957 to 2019. The data were collected through the Scopus database and processed with analytical and bibliometric techniques. The selection of the keywords is an essential step, because ELF has a very different meaning in some areas of medicine, where it is associated with a gene. A total of 12,436 documents were worked on in 12 thematic communities according to their collaborative relationships between authors and documents. Studies included authors publishing in the different thematic areas and the country where the USA stands first with more researchers in this theme than China and Japan. Documents were analyzed from the temporal perspective, their overall contribution, means of publication, and the language of the publication. Research requires extra effort and multidisciplinary collaboration to improve the knowledge, the application, and influence of these fields.

scholarly journals Observation of a new type of low-frequency waves at comet 67P/Churyumov-Gerasimenko

2015 ◽  
Vol 33 (8) ◽  
pp. 1031-1036 ◽  
Author(s):  
I. Richter ◽  
C. Koenders ◽  
H.-U. Auster ◽  
D. Frühauff ◽  
C. Götz ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Low Frequency ◽  
Field Measurements ◽  
New Type ◽  
Current Instability ◽  
Interaction Regions ◽  
Activity State ◽  
Comet 67P ◽  
Low Frequency Waves ◽  
Made In

Abstract. We report on magnetic field measurements made in the innermost coma of 67P/Churyumov-Gerasimenko in its low-activity state. Quasi-coherent, large-amplitude (δ B/B ~ 1), compressional magnetic field oscillations at ~ 40 mHz dominate the immediate plasma environment of the nucleus. This differs from previously studied cometary interaction regions where waves at the cometary ion gyro-frequencies are the main feature. Thus classical pickup-ion-driven instabilities are unable to explain the observations. We propose a cross-field current instability associated with newborn cometary ion currents as a possible source mechanism.

scholarly journals Low-frequency waves at comet 67P/Churyumov-Gerasimenko

2016 ◽  
Vol 594 ◽  
pp. A66 ◽  
Author(s):  
C. Koenders ◽  
C. Perschke ◽  
C. Goetz ◽  
I. Richter ◽  
U. Motschmann ◽  
...  
Keyword(s):  
Low Frequency ◽  
Comet 67P ◽  
Low Frequency Waves
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