The Super Dual Auroral Radar Network (SuperDARN) has been operating as an international co-operative organization for over 10 years. The network has now grown so that the fields of view of its 18 radars cover the majority of the northern and southern hemisphere polar ionospheres. SuperDARN has been successful in addressing a wide range of scientific questions concerning processes in the magnetosphere, ionosphere,

In an attempt to place short-lived, high-speed magnetotail flows termed bursty bulk flow events (BBFs) in the context of substorm phenomenology we analyze one such event that took place on April 11, 1985, using data from several spacecraft and many ground stations. The substorm onset, which took place at 0127 UT, had a meridian 2 hours of local time east of AMPTE/IRM. The satellite did not detect high-speed flows at that time. A high-latitude (--•70 ø corrected geomagnetic) substorm intensification took place at 0202 UT centered --•0.5 hour of local time west of the AMPTE/IRM meridian. The ISEE 2 satellite at the magnetotail lobe and the LANL 019 satellite at geosynchronous altitude were both at the same meridian as AMPTE/IRM at the time. The 0202 UT substorm intensification was associated with (1) a dipolarization at the ISEE 2 satellite at 0200:30 UT, (2) a BBF onset at AMPTE/IRM at 0202 UT accompanied by an intense dipolarization consistent with current wedge formation, (3) an energetic particle injection at geosynchronous altitude that took place at 0204 UT. The plasma acceleration region associated with this substorm intensification was estimated to be --• 8 R E tailward of AMPTE/IRM. Thus, during this activity the BBF event was due to an observed tail collapse Earthward of X --• -26 RE. The Earthward energy transport measured at AMPTE/IRM can account for the expected magnetospheric power consumption if the BBF has a cross-sectional area of only 1-2 R2e in the Y-Z direction. Similarly, the Earthward magnetic flux transport rate measured at AMPTE/IRM during the BBF event can result in a potential drop comparable to the expected transpolar cap potential if the BBF event has a size of 1-2 R E in the Y direction. The large amounts of flux transport measured past the satellite necessitate the existence of lobe flux reconnection tailward of AMPTE/IRM. The above results assume the validity of the frozen-in condition over the --•10-min duration of the BBF event.Although activity continued in the ionosphere and the ring current for well over 1.5 hours after the 0202 UT substorm intensification, most of the earthward energy and magnetic flux transport past IRM had ceased --•10 min after the BBF onset. We propose that the fast flows transport and pile up magnetic flux through a very narrow (a few R E in Y extent) flow channel in the midtail to the edge of an expanding dipolarization front in the near-Earth region. After the plasma sheet dipolarizes at a given location enhanced flux transport ceases, resulting in an apparent short (10-min timescale) duration of the fast flows. Unlike the near-Earth plasma sheet, which dipolarizes across many hours of local time, the midtail plasma sheet may exhibit longitudinally localized dipolarization. This may explain the often observed lack of one-to-one correlation between midtail activity and substorms.

[1] We have carried out a direct comparison of pulsating auroras observed from the ground at Syowa Station in Antarctica and on board the FAST satellite ($3100 km altitude), with reference to simultaneous data obtained by a Syowa-Iceland conjugate pair of observatories. The aurora at Syowa appeared as east-west aligned bands consisting of two different types: a poleward moving oscillation and a standing oscillation, each with a period of $6 s. Spatial and temporal variations of the downgoing high-energy (>5 keV) electron flux obtained by FAST showed a one-to-one correspondence with the optical pulsating aurora. The occurrence regions of the two different types of pulsating aurora were separated by a narrow gap ($7-10 km in width at 100 km altitude) in the inverted-V structure, and the gaps were colocated with the small-scale upward field-aligned currents. The time-varying magnetic fields (upward field-aligned current) observed by FAST were almost correlated (in-phase) with the downgoing electron flux (>5 keV) modulations. Both the optical emission intensity at Syowa and the downgoing high-energy electron flux (>7 keV) on board FAST showed $3 Hz modulation. The $3 Hz fine structure constituted the main body of the $6 s pulsating aurora. VLF wave activities were not observed by FAST in the region of pulsating aurora. The source regions of the generation or modulation of the energetic particles are estimated to be at a higher altitude than FAST, in the region of $2 Re to 6 Re from the satellite. This suggests that the source region is not located in the equatorial plane of the magnetosphere but is located earthward, far from the equatorial plane. The conjugate pair observations on the ground revealed that the aurora, though pulsating in both hemispheres, was not conjugate in shape, appearing as an east-west aligned band in the Southern Hemisphere but as a torch structure (omega band) in the Northern Hemisphere. The evidence presented in this study suggests that ionosphere-magnetosphere coupling processes are important in producing the pulsating aurora.

Auroral beads, i.e., azimuthally arrayed bright spots resembling a pearl necklace, have recently drawn attention as a possible precursor of auroral substorms. We used simultaneous, ground‐based, all‐sky camera observations from a geomagnetically conjugate Iceland‐Syowa Station pair to demonstrate that the auroral beads, whose wavelength is ∼30–50 km, evolve synchronously in the northern and southern hemispheres and have remarkable interhemispheric similarities. In both hemispheres: 1) they appeared almost at the same time; 2) their longitudinal wave number was similar ∼300–400, corresponding bead separation being ∼1° in longitude; 3) they started developing into a larger scale spiral form at the same time; 4) their propagation speeds and their temporal evolution were almost identical. These interhemispheric similarities provide strong evidence that there is a common driver in the magnetotail equatorial region that controls the major temporal evolution of the auroral beads; thus, the magnetosphere plays a primary role in structuring the initial brightening arc in this scale size.

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We analyze ionospheric convection pat terns over the polar regions during the passage of an interplanetary magnetic cloud on January 14, 1988, when the interplanetary magnetic field (IMF) rotated slowly in direction and had a large amplitude. Using the assirnilative mapping of ionospheric electrodynamics (AMIE) procedure, we combine simultaneous observations of ionospheric drifts and magnetic perturbations from many different instruments into consistent patterns of high-latitude electrodynamics, focusing on the period of northward IMF. By combining satellite data with ground-based observations, we have generated one of the most comprehensive data sets yet assembled and used it to produce convection maps for both hemispheres. We present evidence that a lobe convection cell was embedded within normal merging convection during a period when the IMF By and B, components were large and positive. As the IMF became predominantly northward, a strong reversed convection pattern (afternoon-to-morning potential drop of around 100 kV) appeared in the southern (

[1] We present a survey of medium-scale traveling ionospheric disturbances (MSTIDs) observed by a Super Dual Auroral Radar Network HF radar located in the Falkland Islands between May 2010 and April 2011. The radar has a field of view that overlooks the Antarctic Peninsula, a known hot spot of gravity wave activity. We present observations of radar ground-backscatter data, in which the signatures of MSTIDs are manifested as structured enhancements in echo power. Observed periods were in the range 30-80 min, corresponding to frequencies of 0.2-0.6 mHz. Wavelengths were generally in the range 200-800 km and phase speeds in the range 100-300 m s -1 . These values are within the ranges typically associated with medium-scale gravity waves. We find a primary population of northward (equatorward) propagating MSTIDs, which demonstrate an association with enhanced solar wind-magnetosphere coupling and a smaller, westward propagating population, that could be associated with atmospheric gravity waves excited by winds over the Andean and Antarctic Peninsula mountains or by the high winds of the Antarctic Polar Vortex.