1. SuperDARN and SCANDI data
Magnetosphere, ionosphere and thermosphere signatures of a Traveling Convection Vortex
M. Lessard1, C. Farrugia1 K. Lynch2, P. Fernandes2, B. Anderson3, J. Moen4, K. Oksavik5, T. Yeoman6, A. Aruliah7, M. Engebretson8, J. Posch8
 1University of New Hampshire, Space Science Center, Durham, NH; 2Dartmouth College, Hanover, NH; 3JHU/APL, Laurel, MD;
4University of Oslo, Oslo, Norway; 5University of Bergen, Bergen, Norway; 6University of Leicester, Leicester, UK
7University College London, UK; 8Augsburg College, Minneapolis, MN
Introduction
Allsky camera, induction coil, EISCAT and AMPERE data
SuperDARN and SCANDI data
During the Rocket Experiment for Neutral Upwelling (RENU) launch campaign in late 2010, the science team spent a number of weeks in Longearbyen observing the ionosphere in support of the launch call. During this time, various instruments were making coordinated measurements, including EISCAT, SCANDI and the AMPERE (Iridium) satellites.
On December 10, the team was fortunate to have a Traveling Convection Vortex (TCV), pass overhead. Here, we present data showing magnetospheric currents observed by AMPERE, corresponding divergence of thermospheric winds observed by SCANDI, as well as EMIC observations from the ground beneath the event as it transited overhead.
SuperDARN data: Equatorward flows are green/blue everywhere (towards Doppler), and poleward flow is yellow/red everywhere (away doppler). The first panel at 0829 looks like a reasonably standard twin cell pattern -- poleward in the central beams, equatorward at the edges. The  and plots show poleward flows in the middle, some equatorward flow to the south of that, and equatorward flow to the west.  It is possible to assign a small clockwise vortex in the middle and a small anticlockwise vortex to the west. By the end of the page at 0833, we have pretty much equatorward flow throughout.
EMIC waves observed at Longyearbyen in conjunction with the TCV (which arrived at approx 0830 UT). EMIC occurrences with TCV have been reported in the past. Similar wave signatures were also observed in Ny Alesund (100 km poleward) and Hornsund (100 km equatorward). The noise burst observed in conjunction with the TCV is also typical.
Allsky camera images at 630 nm, acquired during the TCV. The emissions occurring poleward of the station before the event are thought to be cusp precipitation. The emissions associated with the TCV are the brief, bright spots directly over Longyearbyen. N E S W
Solar wind data from WIND, near L1. The clock angle (bottom panel, i.e, polar angle in GSM YZ plane) shows a northward pointing field. The proton beta and Alfven Mach number (~ 1 and 10, respectively) are very typical of the solar wind at 1 AU. The dynamic pressure changes from ~7 to 7:20 UT (in a low Pdyn background) and the concomitant changes in clock angle brought about by changes in Bz are likely to be the cause of the TCV seen in magnetometer data.
TCV Signature
SCANDI observations of neutral winds over Longyearbyen. Before the TCV passed, winds were quite uniform. Then, beginning near 0833 UT, winds equartorward of the station decrease significantly, followed by a clear divergence in the 0840 UT image. No clear signature of a temperature increase is observable in the SCANDI data (these data not shown).
Summary
A Traveling Convection Vortex was observed that passed directly over Longyearbyen and through the EISCAT radar beam, as well as the allsky camera field-of-view. Brief, but clear heating was observed in the EISCAT data.
Induction coil magnetometers show the onset of EMIC waves at the approximate time of the TCV arrivval, presumably driven by a pressure pulse in the solar wind. These waves persisted for nearly an hour.
AMPERE (Iridium) data show weak magnetic perturbations associated with the auroral currents.
SuperDARN flows show, perhaps, direct observations of vortical flows.
SCANDI data show a divergence in thermospheric winds, presumably due to heating associated with the flows. However, temperature enhancements in the neutrals are not observed.
EISCAT data, showing electron and ion temperature enhancements, with corresponding density increases from the soft precipitation.
AMPERE (Iridium) data, showing current signatures in AACGM coordinates. During the event, LYR was located near 1130 MLT and at ILAT~75 degrees (red arrow).
Magnetometer data from the IMAGE chain, showing the passage of the TCV at 0830 UT
Acknowledgement: Research at the University of New Hampshire was supported by NASA grant NNX08AN21G and NSF grants ARC We thank the institutes who maintain the IMAGE Magnetometer Array.