Distribution of EMIC wave event locations depending on their distance from the magnetopause

0489539 - ÚFA 2019 DE eng A - Abstrakt
Grison, Benjamin - Hanzelka, Miroslav - Basovník, Marek - Usanova, M. - Souček, Jan - Santolík, Ondřej
Distribution of EMIC wave event locations depending on their distance from the magnetopause.
Geophysical Research Abstracts. Vol. 20. Göttingen: European Geosciences Union, 2018. EGU2018-4367-1, s. 15662. E-ISSN 1607-7962.
[EGU General Assembly 2018. 08.04.2018-13.04.2018, Vienna]
Institucionální podpora: RVO:68378289
Klíčová slova: magnetosphere * electromagnetic ion cyclotron (EMIC) * plasma waves
Obor OECD: Fluids and plasma physics (including surface physics)
https://meetingorganizer.copernicus.org/EGU2018/EGU2018-15662.pdf

Wave particle interactions play an important role in the magnetosphere dynamics. ElectroMagnetic ion cyclotron (EMIC) waves are one of the kind of plasma waves involved in these interactions. Afterthefirstinsituobservations of EMIC waves close to the plasmapause, many statistical studies pointed out that the dayside magnetosphere region close to the magnetopause is the place where the EMIC occurrence rate is the highest. In this region the EMICwaveoccurrenceisrelatedtomagnetospherecompressionevents,inrelationwithsolarwindkineticpressure increases. ThepresentationoftheEMICoccurrencerateisusuallymadewithrespecttotheL-shellvalueoftheobservations (theL-shellvalueofalocationinthemagnetospherebeingthedistancetotheEarth(inEarthradii),inthemagnetic equatorial plane, of the magnetic field line passing through this location). The L-shell value of the region adjacent to the magnetopause can vary by few Earth radii in respect with the solar pressure. InthepresentstudyweproposetorepresenttheEMICwaveoccurrenceinthedaysidemagnetospherewithrespect to the distance from the magnetopause. This provides a new insight of the EMIC wave distribution in this region and a better understanding of the magnetosphere compression influence on the EMIC wave onset. The THEMIS mission offers the best data set for this: THEMIS instruments observed EMIC emissions in this region and the the orbits of the spacecraft (THEMIS/C, D, E and to a lower extent A) often cross the region of interest, including the magnetopause. The magnetopause position is estimated with the Shue et al. model (1998) and compared to the observed position, when possible. We propose here to present in detail our method and the first results of the EMIC occurrence rate in function of their distance to the magnetopause. Our study is based on EMIC waves events by Usanova et al. (2012) based on FluxGateMagnetometersmeasurementsonboardTHEMISspacecraft.Theinfluenceofthesolarwindpressureis also discussed.
Trvalý link: http://hdl.handle.net/11104/0283933