Conjugate Ground-Spacecraft Observations of VLF Chorus Elements

0487718 - ÚFA 2018 RIV US eng J - Článek v odborném periodiku
Demekhov, A. G. - Manninen, J. - Santolík, Ondřej - Titova, E. E.
Conjugate Ground-Spacecraft Observations of VLF Chorus Elements.
Geophysical Research Letters. Roč. 44, č. 23 (2017), s. 11735-11744. ISSN 0094-8276. E-ISSN 1944-8007
Grant ostatní: AV ČR(CZ) AP1401
Program: Akademická prémie - Praemium Academiae
Institucionální podpora: RVO:68378289
Klíčová slova: VAN ALLEN PROBES * WHISTLER-MODE WAVES * MAGNETOSPHERIC CHORUS * PROPAGATION * EMISSIONS * BAND * FREQUENCY * AMPLITUDE * MASER * GUIDE
Obor OECD: Fluids and plasma physics (including surface physics)
Impakt faktor: 4.339, rok: 2017
http://onlinelibrary.wiley.com/doi/10.1002/2017GL076139/epdf

We present results of simultaneous observations of VLF chorus elements at the ground-based station Kannuslehto in Northern Finland and on board Van Allen Probe A. Visual inspection and correlation analysis of the data reveal one-to-one correspondence of several (at least 12) chorus elements following each other in a sequence. Poynting flux calculated from electromagnetic fields measured by the Electric and Magnetic Field Instrument Suite and Integrated Science instrument on board Van Allen Probe A shows that the waves propagate at small angles to the geomagnetic field and oppositely to its direction, that is, from northern to southern geographic hemisphere. The spacecraft was located at L similar or equal to 4.1 at a geomagnetic latitude of -12.4 degrees close to the plasmapause and inside a localized density inhomogeneity with about 30% density increase and a transverse size of about 600 km. The time delay between the waves detected on the ground and on the spacecraft is about 1.3 s, with ground-based detection leading spacecraft detection. The measured time delay is consistent with the wave travel time of quasi-parallel whistler-mode waves for a realistic profile of the plasma density distribution along the field line. The results suggest that chorus discrete elements can preserve their spectral shape during a hop from the generation region to the ground followed by reflection from the ionosphere and return to the near-equatorial region.
Trvalý link: http://hdl.handle.net/11104/0282366