Observations of lion roars in the magnetosheath by the STAFF/DWP experiment on the Double Star TC-1 spacecraft

Lion roars are intense, short duration packets of whistler mode waves, observed in the magnetosheath. They are typically seen coincident with the magnetic field minima of mirror mode waves. The orbit of the Double Star TC-1 spacecraft (570 km by 78970 km, inclination at 28.5 degrees) is...

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Main Authors: K. H. Yearby, H. S. C. Alleyne, N. Cornilleau-Wehrlin, O. Santolik, M. A. Balikhin, S. N. Walker, A. Fazakerley, A. Lahiff
Format: Article
Language:English
Published: Copernicus Publications 2005-11-01
Series:Annales Geophysicae
Online Access:https://www.ann-geophys.net/23/2861/2005/angeo-23-2861-2005.pdf
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author K. H. Yearby
H. S. C. Alleyne
N. Cornilleau-Wehrlin
O. Santolik
O. Santolik
M. A. Balikhin
S. N. Walker
A. Fazakerley
A. Lahiff
author_facet K. H. Yearby
H. S. C. Alleyne
N. Cornilleau-Wehrlin
O. Santolik
O. Santolik
M. A. Balikhin
S. N. Walker
A. Fazakerley
A. Lahiff
author_sort K. H. Yearby
collection DOAJ
description Lion roars are intense, short duration packets of whistler mode waves, observed in the magnetosheath. They are typically seen coincident with the magnetic field minima of mirror mode waves. The orbit of the Double Star TC-1 spacecraft (570 km by 78970 km, inclination at 28.5 degrees) is ideal for observations of lion roars as the spacecraft is in the magnetosheath more than 50% of the time when the apogee is on the dayside. The STAFF/DWP experiment provides the spectral matrix of the three magnetic components at 27 frequencies in the range 10 Hz to 4 kHz, with one second time resolution, and also the waveform up to 180 Hz at a low duty cycle. The characteristics of lion roars observed are reported. The maximum lion roar intensities appear higher than reported by most previous studies. The electron temperature anisotropy is estimated from the lion roar frequency ratios, and is in reasonably good agreement with plasma measurements. This indicates the presence of a trapped electron component in the mirror mode.
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spelling doaj.art-a2b01390332d4feab20191feace1984a2022-12-22T03:23:18ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762005-11-01232861286610.5194/angeo-23-2861-2005Observations of lion roars in the magnetosheath by the STAFF/DWP experiment on the Double Star TC-1 spacecraftK. H. Yearby0H. S. C. Alleyne1N. Cornilleau-Wehrlin2O. Santolik3O. Santolik4M. A. Balikhin5S. N. Walker6A. Fazakerley7A. Lahiff8ACSE, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UKACSE, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UKCETP/IPSL, 10–12 Av. de l’Europe, 78 140 Vélizy, FranceFaculty of Mathematics and Physics, Charles University, V Holesovickach 2, 18 000 Praha 8, Czech RepublicInstitute of Atmospheric Physics, Bocni II/1401, 14 131 Praha 4, Czech RepublicACSE, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UKACSE, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UKMullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, UKMullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, UKLion roars are intense, short duration packets of whistler mode waves, observed in the magnetosheath. They are typically seen coincident with the magnetic field minima of mirror mode waves. The orbit of the Double Star TC-1 spacecraft (570 km by 78970 km, inclination at 28.5 degrees) is ideal for observations of lion roars as the spacecraft is in the magnetosheath more than 50% of the time when the apogee is on the dayside. The STAFF/DWP experiment provides the spectral matrix of the three magnetic components at 27 frequencies in the range 10 Hz to 4 kHz, with one second time resolution, and also the waveform up to 180 Hz at a low duty cycle. The characteristics of lion roars observed are reported. The maximum lion roar intensities appear higher than reported by most previous studies. The electron temperature anisotropy is estimated from the lion roar frequency ratios, and is in reasonably good agreement with plasma measurements. This indicates the presence of a trapped electron component in the mirror mode.https://www.ann-geophys.net/23/2861/2005/angeo-23-2861-2005.pdf
spellingShingle K. H. Yearby
H. S. C. Alleyne
N. Cornilleau-Wehrlin
O. Santolik
O. Santolik
M. A. Balikhin
S. N. Walker
A. Fazakerley
A. Lahiff
Observations of lion roars in the magnetosheath by the STAFF/DWP experiment on the Double Star TC-1 spacecraft
Annales Geophysicae
title Observations of lion roars in the magnetosheath by the STAFF/DWP experiment on the Double Star TC-1 spacecraft
title_full Observations of lion roars in the magnetosheath by the STAFF/DWP experiment on the Double Star TC-1 spacecraft
title_fullStr Observations of lion roars in the magnetosheath by the STAFF/DWP experiment on the Double Star TC-1 spacecraft
title_full_unstemmed Observations of lion roars in the magnetosheath by the STAFF/DWP experiment on the Double Star TC-1 spacecraft
title_short Observations of lion roars in the magnetosheath by the STAFF/DWP experiment on the Double Star TC-1 spacecraft
title_sort observations of lion roars in the magnetosheath by the staff dwp experiment on the double star tc 1 spacecraft
url https://www.ann-geophys.net/23/2861/2005/angeo-23-2861-2005.pdf
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