Abstract
Using the Equator-S spacecraft and SuperDARN HF radars an extensive survey of bursty reconnection at the magnetopause and associated flows in the polar ionosphere has been conducted. Flux transfer event (FTE) signatures were identified in the Equator-S magnetometer data during periods of magnetopause contact in January and February 1998. Assuming the effects of the FTEs propagate to the polar ionosphere as geomagnetic field-aligned-currents and associated Alfvén-waves, appropriate field mappings to the fields-of-view of SuperDARN radars were performed. The radars observed discrete ionospheric flow channel events (FCEs) of the type previously assumed to be related to pulse reconnection. Such FCEs were associated with \sim80% of the FTEs and the two signatures are shown to be statistically associated with greater than 99% confidence. Exemplary case studies highlight the nature of the ionospheric flows and their relation to the high latitude convection pattern, the association methodology, and the problems caused by instrument limitations.Key words: Ionosphere (polar ionosphere) · Magnetospheric physics (magnetosphere-ionosphere interaction; solar wind-magnetosphere interactions)
Highlights
A variety of transient high-latitude ionospheric phenomena observed by diverse instruments have been associated with bursty reconnection of the geomagnetic ®eld and the interplanetary magnetic ®eld (IMF) near the magnetopause
87 Flux transfer event (FTE) were observed by Equator-S when it geomagnetically mapped to the ®elds-of-view of the Northern Hemisphere SuperDARN radars and 112 FCEs were observed by radars in the polar ionosphere conjugate to the Equator-S spacecraft during the periods of Equator-S magnetopause proximity
More likely is that Equator-S did not observe the FTEs as the reconnection site moved away from it whilst FCEs continued to be observed in the ionosphere as in case study (c)
Summary
A variety of transient high-latitude ionospheric phenomena observed by diverse instruments have been associated with bursty reconnection of the geomagnetic ®eld and the interplanetary magnetic ®eld (IMF) near the magnetopause. These include pulsed auroral phenomena (Sandholt et al, 1985) and associated transientows (Lockwood et al, 1989; Pinnock et al, 1993). HF radars have observed high velocityow channels in the ionospheric F-region that have been assumed to be the response to transient reconnection (Pinnock et al 1993, 1995; Rodger and Pinnock 1997) Their spatial extent, ̄ow orientation, MLT occurrence, and dependence on IMF By have been extensively examined (Provan et al 1998, 1999; Provan and Yeoman, 1999).
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