A seasonal variation in the convection responce to IMF orientation

Abstract

We investigate the response of dayside convection, measured by the CUTLASS Finland HF radar, to differing orientations of the interplanetary magnetic field (IMF), determined by the ACE spacecraft, for solstice and equinox periods during 1998, 1999, and 2000. Our results indicate that the influence of the B y component of the IMF on the convection flow differs from season to season, suggesting an interhemispheric asymmetry in convection excitation; the influence of B y is greatest near summer solstice and in the pre-noon sector. The influence of IMF B z remains the same throughout the year.