Statistical study of lion roar emissions observed by the cluster spacecraft

0442089 - ÚFA 2015 RIV US eng C - Conference Paper (international conference)
Krupař, Vratislav - Santolík, Ondřej - Souček, Jan
Statistical study of lion roar emissions observed by the cluster spacecraft.
General Assembly and Scientific Symposium (URSI GASS), 2014 XXXIth URSI. New York: IEEE, 2014, s. 1-4. ISBN 978-1-4673-5225-3.
[URSI General Assembly and Scientific Symposium (URSI GASS) 2014 /31./. Beijing (CN), 16.08.2014-23.08.2014]
R&D Projects: GA ČR(CZ) GAP209/12/2394; GA ČR GAP205/10/2279
Institutional support: RVO:68378289
Keywords : whistler-mode waves * Earth’s magnetosheath * Cluster spacecraft
Subject RIV: BL - Plasma and Gas Discharge Physics
http://ieeexplore.ieee.org/xpl/abstractAuthors.jsp?reload=true&arnumber=6929932

Lion roars are intense narrow-band whistler-mode emissions with typical frequencies about 100 Hz. They are frequently occurring in the Earth's magnetosheath. They are thought to be generated by local electron temperature instabilities. The four CLUSTER spacecraft allow us to study the Earth's magnetospehere and its interaction with the solar wind in three dimensions. We have identified about 5000 time-frequency intervals containing the lion roar emissions during 2001 and 2005 in the data of the Spatio Temporal Analysis Field Fluctuations – Spectral Analyzer (STAFF-SA). We present results of a statistical study of Lion roar’s spatial, frequency and wave power distribution. We have found that Lion roars are more often observed on the dawn side than on the dusk side of the magnetosheath. We have investigated the orientation of Poyting vector directions of Lion roars calculated from measured spectral matrices using the Singular Value Decomposition (SVD).
Permanent Link: http://hdl.handle.net/11104/0245486