Abstract
The DOPE (Doppler Pulsation Experiment) HF Doppler sounder located near Tromsø, Norway (geographic: 69.6°N 19.2°E; L = 6.3) is deployed to observe signatures, in the high-latitude ionosphere, of magnetospheric ULF waves. A type of wave has been identified which exhibits no simultaneous ground magnetic signature. They can be subdivided into two classes which occur in the dawn and dusk local time sectors respectively. They generally have frequencies greater than the resonance fundamentals of local field lines. It is suggested that these may be the signatures of high-m ULF waves where the ground magnetic signature has been strongly attenuated as a result of the scale size of the waves. The dawn population demonstrate similarities to a type of magnetospheric wave known as giant (Pg) pulsations which tend to be resonant at higher harmonics on magnetic field lines. In contrast, the waves occurring in the dusk sector are believed to be related to the storm-time Pc5s previously reported in VHF radar data. Dst measurements support these observations by indicating that the dawn and dusk classes of waves occur respectively during geomagnetically quiet and more active intervals.Key words. Ionosphere (auroral ionosphere; ionosphere-magnetosphere interactions) · Magnetospheric physics (MHD waves and instabilities)
Highlights
An important coupling mechanism between the magnetosphere and the ionosphere is ultra low frequency (ULF) waves, since they transfer both energy and Correspondence to: D
A commonly occurring type of ULF wave signature observed by the Doppler Pulsation Experiment (DOPE) sounder are those with no associated ground magnetic signature detected by nearby magnetometers
In order to establish that the uncorrelated events observed by DOPE are signatures caused by incident
Summary
An important coupling mechanism between the magnetosphere and the ionosphere is ultra low frequency (ULF) waves, since they transfer both energy and Correspondence to: D. These processes are most signi®cant in the high-latitude ionosphere, where the magnetosphereionosphere interaction is strongest. The waves act as an important diagnostic of magnetospheric morphology and dynamics. Yeoman et al, 1990) for magnetospheric magnetohydrodynamic (MHD) wave modes and controls the transfer of energy and momentum. It modi®es the magnetospheric wave signature, leading to rotation and attenuation of the wave magnetic signature detected on the ground The ionospheric signature of ULF waves is an important topic of study
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
