Journal metrics

Journal metrics

  • IF value: 1.621 IF 1.621
  • IF 5-year value: 1.614 IF 5-year 1.614
  • CiteScore value: 1.61 CiteScore 1.61
  • SNIP value: 0.900 SNIP 0.900
  • SJR value: 0.910 SJR 0.910
  • IPP value: 1.58 IPP 1.58
  • h5-index value: 24 h5-index 24
  • Scimago H index value: 80 Scimago H index 80
Ann. Geophys., 36, 793-808, 2018
https://doi.org/10.5194/angeo-36-793-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Regular paper
24 May 2018
Statistical analysis of mirror mode waves in sheath regions driven by interplanetary coronal mass ejection
Matti M. Ala-Lahti1, Emilia K. J. Kilpua1, Andrew P. Dimmock2,3, Adnane Osmane2, Tuija Pulkkinen2, and Jan Souček4 1Department of Physics, P.O. Box 64, University of Helsinki, Helsinki, Finland
2Aalto University, School of Electrical Engineering, Espoo, Finland
3Swedish Institute of Space Physics, Uppsala, Sweden
4Institute of Atmospheric Physics, Czech Academy of Sciences, Prague, Czech Republic
Abstract. 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 Alfvén 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.
Citation: Ala-Lahti, M. M., Kilpua, E. K. J., Dimmock, A. P., Osmane, A., Pulkkinen, T., and Souček, J.: Statistical analysis of mirror mode waves in sheath regions driven by interplanetary coronal mass ejection, Ann. Geophys., 36, 793-808, https://doi.org/10.5194/angeo-36-793-2018, 2018.
Publications Copernicus
Download
Short summary
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) to deepen our understanding of these geo-effective plasma environments. The results imply that mirror modes are common structures in ICME sheaths and occur almost exclusively as dip-like structures and in mirror stable stable plasma.
We present a comprehensive statistical analysis of mirror mode waves and the properties of their...
Share