SUPER DUAL AURORAL RADAR NETWORK OBSERVATIONS OF CONVECTION DURING A PERIOD OF SMALL-MAGNITUDE NORTHWARD IMF

Observations of the high-latitude northern hemisphere convection patte rn are presented for varying small-magnitude interplanetary magnetic f ield (IMF) conditions. A new data analysis technique is used which mak es use of all available data from the SuperDARN network rather than on ly using data from the regions of overlap of radar fields of view. Usi ng this technique, the area over which convection is determined is oft en greatly extended from the region of overlap. The IMF during this pe riod was small magnitude, \B\ < 4 nT. During one interval, IMF B-z was northward, while B-y was nearly zero. Convection during this interval evolved to a pattern with a large dusk cell with flow across the noon meridian from dusk toward dawn. In a later interval, IMF B-z and B-y were both nearly zero. During this interval, convection evolved to a f our-cell pattern. Comparison of the observations with conceptual model s showed significant differences for both intervals. During the first interval, statistical models and the observations compared favorably. During the second interval, however, the observations showed a signifi cantly different pattern from the first interval, while statistical mo dels predict the same pattern for both intervals. The behavior of the convection pattern can be in part ascribed to the role played by B-x, which was the dominant IMF component throughout this interval.