Sökning: onr:"swepub:oai:DiVA.org:kth-27103" >
Radar detection of ...
Radar detection of a localized 1.4 Hz pulsation in auroral plasma, simultaneous with pulsating optical emissions, during a substorm
-
Cosgrove, R. (författare)
-
Nicolls, M. (författare)
-
- Dahlgren, Hanna (författare)
- KTH,Rymd- och plasmafysik
-
visa fler...
-
Ranjan, S. (författare)
-
Sanchez, E. (författare)
-
Doe, R. (författare)
-
visa färre...
-
(creator_code:org_t)
- 2010-10-29
- 2010
- Engelska.
-
Ingår i: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 28:10, s. 1961-1979
- Relaterad länk:
-
https://www.ann-geop...
-
visa fler...
-
https://urn.kb.se/re...
-
https://doi.org/10.5...
-
visa färre...
Abstract
Ämnesord
Stäng
- Many pulsating phenomena are associated with the auroral substorm. It has been considered that some of these phenomena involve kilometer-scale Alfven waves coupling the magnetosphere and ionosphere. Electric field oscillations at the altitude of the ionosphere are a signature of such wave activity that could distinguish it from other sources of auroral particle precipitation, which may be simply tracers of magnetospheric activity. Therefore, a ground based diagnostic of kilometer-scale oscillating electric fields would be a valuable tool in the study of pulsations and the auroral substorm. In this study we attempt to develop such a tool in the Poker Flat incoherent scatter radar (PFISR). The central result is a statistically significant detection of a 1.4 Hz electric field oscillation associated with a similar oscillating optical emission, during the recovery phase of a substorm. The optical emissions also contain a bright, lower frequency (0.2 Hz) pulsation that does not show up in the radar backscatter. The fact that higher frequency oscillations are detected by the radar, whereas the bright, lower frequency optical pulsation is not detected by the radar, serves to strengthen a theoretical argument that the radar is sensitive to oscillating electric fields, but not to oscillating particle precipitation. Although it is difficult to make conclusions as to the physical mechanism, we do not find evidence for a plane-wave-like Alfven wave; the detected structure is evident in only two of five adjacent beams. We emphasize that this is a new application for ISR, and that corroborating results are needed.
Ämnesord
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Nyckelord
- Ionosphere
- Auroral ionosphere
- Ionosphere-magnetosphere interactions
- Magnetospheric physics
- Storms and substorms
- Astronomy and astrophysics
- Astronomi och astrofysik
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
Hitta via bibliotek
Till lärosätets databas