Multievent Study of Characteristics and Propagation of Naturally Occurring ELF/VLF Waves Using High‐Latitude Ground Observations and Conjunctions With the Arase Satellite. Issue 2 (12th February 2021)

• Record Type: Journal Article
• Authors: Martinez‐Calderon, C.; Katoh, Y.; Manninen, J.; Santolik, O.; Kasahara, Y.; Matsuda, S.; Kumamoto, A.; Tsuchiya, F.; Matsuoka, A.; Shoji, M.; Teramoto, M.; Shinohara, I.; Shiokawa, K.; Miyoshi, Y.
• Is Part Of: Journal of geophysical research. Volume 126:Issue 2(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-02-12
• Subjects: Arase -- conjugated event -- ERG -- ionospheric exit point -- VLF -- whistler‐mode waves; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2020JA028682
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: We report the properties of the ionospheric exit point and characteristics of several types of very low frequency waves, including chorus and quasiperiodic emissions, based on a comprehensive dataset of simultaneous observations between ground and space. Whistler‐mode waves were observed at Kannuslehto (L = 5.5, KAN), Finland, and in the inner magnetosphere by the Japanese Arase satellite. During the 2017–2018 winter campaign, we found 13 cases showing one‐to‐one correspondence of wave spectra between KAN and Arase. This is the first time that such a large number of conjugated events have been reported at once. The duration of the events ranged from a few minutes up to 3 h, with 90% of events detected in the afternoon sector. While the occurrence rate is higher during daytime, this can also be related to a majority of the detected waves being quasiperiodic emissions, a known dayside phenomenon. Arase was usually located within 30° of the equator, at L ∼4–5, and detected mostly waves propagating at oblique angles (≥20°). Frequently, the ionospheric magnetic footprint of Arase was located equatorwards (south) from KAN, often in the same geographical area. We investigated the probable location of the ionospheric exit point of the waves from the location of the footprint of Arase and the angle of arrival of waves detected at KAN. Using density measurements at Arase we discuss magnetospheric wave propagation; we find that, in most cases, waves were unducted in their propagation from the satellite to the ground. Key Points: First time such a large number (13) of space‐ground conjugated events of magnetospheric whistler‐mode ELF/VLF waves is reported Ionospheric exit point of the waves is usually located at least ∼250 km equatorwards (south) of ground station in Finland at L ∼5.5 All conjugated events but one were observed on the afternoon side of the magnetosphere