Tracing Geomagnetic Conjugate Points by means of Extremely Similar Interhemispheric AurorasN. Sato (1), A. Kadokura (1), Y. Ebihara (1) , H. Deguchi (1), and T. Saemundsson (2)

National Institute of Polar Research, Tokyo, Japan (nsato@nipr.ac.jp)Science Institute, University of Iceland, IcelandNational Institute of Polar Research (NIPR)IAGA 2005

Auroral Conjugate Observation at Syowa and IcelandVisualization of the conjugate foot prints of the geomagnetic field lines

Mapping of Northern/Southern hemispheres with geomagnetic coordinate

Conjugate point of Syowa Station (IGRF model)Comparison of geomagnetic parameters (Epoch: 23:20:00 UT, 26 Sep, 2003)

StationGlat (deg)Glon (deg)Inv.lat (deg)Mlon (deg)MLT (hr)at 0.0 UTL valueD (deg)I (deg)B (nT)Tjornes66.20-17.1266.4171.2623.466.25 -16.2176.5752321Syowa-69.0039.5866.2771.7523.496.17-48.68-63.6143178

All-Sky Image and Geomagnetic meshat 120 km altitudeTJORNESSYOWAat 23:23:00 UT on Sep. 26, 2003Magnetic zenith

Projection on Geomagnetic planeat 120 km altitudeTJORNESSYOWAat 23:23:00 UT on Sep. 26, 2003 (elevation > 10)

Abstract of the Syowa-Iceland Auroral Conjugate Observation, so farStarting from 1984 (20 years anniversaryExecuted every year in the equinox season, mainly in September, for about two weeksSimultaneous darkness for about 4 hoursOnly 23 nights of simultaneous observation in one season, mainly due to weather conditionGood conjugate event is rare

September 26, 2003 event : The best conjugate event in the 20 year history

Instruments at conjugate stations

SYOWAIcelandFluxgate magnetometerInduction magnetometerRiometerVLF receiverImaging RiometerAll-sky TV camera (only equinox)All-sky monochromatic Imager (from 2005)Meridian Scanning PhotometerFabry-Perot ImagerSuperDARN radarMF-radarIonospheric vertical sounderVHF Doppler radar

Iceland UK SAMNET magnetic meridian

September 26, 2003 eventSAMNET data Pi2 onset : 23:18 UT Onset occurred at westward of Iceland meridian

TJRTJRTJRSYWSYWSYWMNSWENMSWESeptember 26, 2003 event all-sky TV data (23:19:3023:23:50 UT, 10 sec interval)

TJRTJRTJRSYWSYWSYWSeptember 26, 2003 event all-sky TV data (23:24:0023:28:20 UT, 10 sec interval)

TJRTJRTJRSYWSYWSYWSeptember 26, 2003 event all-sky TV data (23:28:3023:32:50 UT, 10 sec interval)

September 26, 2003 event Total Intensity & E-W KeogramTIME (UT)

Finding one-to-one correspondenceTracing temporal variation of conjugate location

Tracing temporal variation of conjugate location of Syowa

IMAGE/FUV WIC and POLAR VIS Earth CameraLongitudinal displacement depending on the clock angle Satellite Observationstgaard et al. (JGR, 2004)

(X, Y, Z)gsm = (29.028.6, 11.112.5, 2.41.9) Re ACE Vsw 500 km/sIMF data Geotail

Magnetic variation at Syowa and TjornesTJRSYWTJRSYWH T)TJRSYWD T)Z T)26-27 September, 2003

Equivalent current & Ionospheric potentialHDZequivalent current & ionospheric potentialBTJRSYWTJRSYW

North-South asymmetry of magnetospheric configuration ?j|| Nj|| SIf BN < BS then NP could be located eastward of SPNPSPdBdBBNBS

Summary The September 26, 2003 event is the best one in the 20 year history of the Syowa-Iceland conjugate auroral observation. Extremely similar auroral activities were observed for more than 1 hour. During the observation, the conjugate point moved about 200 km in longitude and about 50 km in latitude. This movement cannot be explained only by the By or clock angle effect of the IMF.North-south asymmetry of magnetospheric configuration could be a cause of the movement.

Overview of the solar geomagnetic condition14-29 September, 2003

September 26, 2003 event All-sky TV data (23:50:0023:55:50 UT, 10 sec interval)TJORNESSYOWA