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Alfvén Ion Cyclotron Waves in Sheath Regions Driven by Interplanetary Coronal Mass Ejections
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SYSNO ASEP 0510735 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Alfvén Ion Cyclotron Waves in Sheath Regions Driven by Interplanetary Coronal Mass Ejections Author(s) Ala-Lahti, M. (FI)
Kilpua, E. K. J. (FI)
Souček, Jan (UFA-U) RID, ORCID
Pulkkinen, T. I. (FI)
Dimmock, A. (SE)Number of authors 5 Source Title Journal of Geophysical Research-Space Physics. - : Wiley - ISSN 2169-9380
Roč. 124, č. 6 (2019), s. 3893-3909Number of pages 17 s. Publication form Print - P Language eng - English Country US - United States Keywords low-frequency waves ; temperature anisotropy ; Earths magnetosheath ; mirror instability ; magnetic clouds ; flux-rope ; origin ; shocks ; CMEs ; fluctuations Subject RIV BL - Plasma and Gas Discharge Physics OECD category Fluids and plasma physics (including surface physics) R&D Projects GA17-08772S GA ČR - Czech Science Foundation (CSF) Method of publishing Open access Institutional support UFA-U - RVO:68378289 UT WOS 000477723100004 EID SCOPUS 85067389484 DOI 10.1029/2019JA026579 Annotation We report on a statistical analysis of the occurrence and properties of Alfven ion cyclotron (AIC) waves in sheath regions driven by interplanetary coronal mass ejections (ICMEs). We have developed an automated algorithm to identify AIC wave events from magnetic field data and apply it to investigate 91 ICME sheath regions recorded by the Wind spacecraft. Our analysis focuses on waves generated by the ion cyclotron instability. AIC waves are observed to be frequent structures in ICME-driven sheaths, and their occurrence is the highest in the vicinity of the shock. Together with previous studies, our results imply that the shock compression has a crucial role in generating wave activity in ICME sheaths. AIC waves tend to have their frequency below the ion cyclotron frequency, and, in general, occur in plasma that is stable with respect to the ion cyclotron instability and has lower ion beta(parallel to) than mirror modes. The results suggest that the ion beta anisotropy beta(perpendicular to)/beta(parallel to) > 1 appearing in ICME sheaths is regulated by both ion cyclotron and mirror instabilities. Workplace Institute of Atmospheric Physics Contact Kateřina Adamovičová, adamovicova@ufa.cas.cz, Tel.: 272 016 012 ; Kateřina Potužníková, kaca@ufa.cas.cz, Tel.: 272 016 019 Year of Publishing 2020 Electronic address https://helda.helsinki.fi/bitstream/10138/305158/1/AICwaves_in_ICMEsheaths.pdf
Number of the records: 1