Statistical analysis of mirror mode waves in sheath regions driven by interplanetary coronal mass ejection

0501832 - ÚFA 2019 RIV DE eng J - Journal Article
Ala-Lahti, M.M. - Kilpua, E. K. J. - Dimmock, A.P. - Osmane, A. - Pulkkinen, T. - Souček, Jan
Statistical analysis of mirror mode waves in sheath regions driven by interplanetary coronal mass ejection.
Annales Geophysicae. Roč. 36, č. 3 (2018), s. 793-808. ISSN 0992-7689. E-ISSN 1432-0576
R&D Projects: GA ČR(CZ) GA17-08772S
Institutional support: RVO:68378289
Keywords : interplanetary physics * plasma waves and turbulence * solar wind plasma * space plasma physics * waves and instabilities
OECD category: Fluids and plasma physics (including surface physics)
Impact factor: 1.585, year: 2018
https://www.ann-geophys.net/36/793/2018/

We present a comprehensive statistical analysis of mirror mode waves and the properties of their plasma surroundings in sheath regions driven by interplanetary coronal mass ejection (ICME). We have constructed a semi-automated method to identify mirror modes from the magnetic field data. We analyze 91 ICME sheath regions from January 1997 to April 2015 using data from the Wind spacecraft. The results imply that similarly to planetary magnetosheaths, mirror modes are also common structures in ICME sheaths. However, they occur almost exclusively as dip-like structures and in mirror stable plasma. We observe mirror modes throughout the sheath, from the bow shock to the ICME leading edge, but their amplitudes are largest closest to the shock. We also find that the shock strength (measured by Alfven Mach number) is the most important parameter in controlling the occurrence of mirror modes. Our findings suggest that in ICME sheaths the dominant source of free energy for mirror mode generation is the shock compression. We also suggest that mirror modes that are found deeper in the sheath are remnants from earlier times of the sheath evolution, generated also in the vicinity of the shock.
Permanent Link: http://hdl.handle.net/11104/0293825