Freja observations of electromagnetic ion cyclotron ELF waves and transverse oxygen ion acceleration on auroral field lines
1994 (English)In: Geophysical Research Letters, ISSN 00948276 (ISSN), Vol. 21, no 17, 1855-1858 p.Article in journal (Refereed) Published
Extremely low-frequency (ELF) magnetic and electric field plasma wave emissions were recorded on 2 October 1993 on auroral field lines by the Magnetic Field Experiment during Freja orbit 4770. The ELF wave frequencies were below the local oxygen gyrofrequency (25 Hz) and between the helium and proton gyrofrequencies (100 to 400 Hz). The ELF waves, interpreted as electromagnetic ion cyclotron (EMIC) waves, were observed in a region of inverted-v-type electron precipitation. The EMIC waves were correlated over time with auroral and lower energy (â‰ˆ 100 eV) electrons, which are both possible sources of free energy, and also with transversely accelerated oxygen ions. The waves above the helium gyrofrequency were more closely correlated with the transverse oxygen ion acceleration than the waves below the oxygen gyrofrequency. These observations are consistent with a scenario in which electron beams generate EMIC waves, which then produce transverse oxygen ion acceleration through a gyroresonant interaction.
Place, publisher, year, edition, pages
1994. Vol. 21, no 17, 1855-1858 p.
Acceleration, Data acquisition, Electric fields, Electron beams, Electrons, Helium, Ions, Magnetic fields, Oxygen, Plasma waves, Satellites, Statistical methods, Auroral field lines, Electric field plasma wave emissions, Electromagnetic ion cyclotron waves, Electron precipitation, Extremely low frequency waves, Freja observations, Gyroresonant interaction, Helium gyrofrequency, Magnetic field plasma wave emissions, Transverse oxygen ion acceleration, Electromagnetic wave emission
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:kth:diva-91726DOI: 10.1029/94GL01363OAI: oai:DiVA.org:kth-91726DiVA: diva2:511088
Correspondence Address: Erlandson, R.E.; Johns Hopkins Univ, Laurel, United States NR 201408052012-03-202012-03-202012-03-20Bibliographically approved